Americans voted in the biggest presidential primary day in US history across 24 states on Super Tuesday. Read and watch how the day unfolded.
10:23 GMT : Washington: The BBC's Jamie Coomarasamy says both Democratic candidates can claim victory, but their prize is to dust themselves down and begin campaigning all over again.
09:12 GMT : Los Angeles : It looks like a comfortable victory for Hillary Clinton in California, says the BBC's Rajesh Mirchandani.
08:45 GMT : "The clarity Democrats so desperately sought escaped them" on Super Tuesday, says Polito.com.
07:57 GMT : John Feehery at The Hill newspaper's Pundits blog writes that the results point to Americans being tired of poll-driven candidates. "Most Americans want to vote for somebody who is real, somebody who shares their values, somebody they can have a beer with... That is why John McCain is doing much better than anybody thought he would."
Hillary Clinton hugs daughter, Chelsea, in New York
07:48 GMT : Missouri : Barack Obama wins the state.
07:26 GMT : Alaska : Mitt Romney to win the state, CNN projects.
06:52 GMT : Blogger Josh Marshall at Talking Points Memo observes that Barack Obama and Hillary Clinton are "two well-funded candidates who've demonstrated an ability to power back from defeats. And neither is going anywhere."
06:37 GMT : CNN estimates that, across the Democratic primaries, Barack Obama got 48% of the popular vote and Hillary Clinton 49%. In the Republican race, the figures given are 40% for John McCain, 31% for Mitt Romney and 21% for Mike Huckabee.
06:18 GMT : Boston : The mood in the Romney camp has been tense and gloomy all night, says the BBC's Kim Ghattas.
HAVE YOUR SAY
No matter who wins, it is a great day for Democracy and a slap to those who want to destroy the Western way of life
06:08 GMT : "Whatever anti-Mitt coordination there is between the two campaigns, McCain is planning to toss overboard Huckabee as soon as he's served his purpose," rather than choose him as a running mate, according to a blog post by Mark Steyn on the National Review.
05:58 GMT : A Romney campaign aide says Wednesday will be a day of "frank discussions" on whether to travel to Kansas on Friday to campaign for its forthcoming caucus, according to NBC's John Yang.
05:53 GMT : Mitt Romney has spent $1.16m per delegate, at which rate it would cost $1.33 billion to win the Republican nomination, the Washington Post estimates. The newspaper says Mike Huckabee has picked up 20 delegates for every $1m spent.
05:45 GMT : Alaska : Barack Obama to win the state, say reports.
05:43 GMT : Blogger Chadwick Matlin on Slate.com's Trailhead blog wonders whether Mitt Romney will now withdraw from the Republican race. "The only region where Romney did especially well was in the mountain West, where Mormons live and news stories go to die. His political life has run its course. It's time to end it."
05:40 GMT : New York : A Clinton campaign spokesman says the battle against Barack Obama is expected to remain "frantic" for another month.
05:34 GMT : The night's real big losers are the right-wing talk show hosts who tried to usher Mitt Romney to the nomination, radio host Ed Schultz tells CNN.
05:24 GMT: The Huffington Post's Bob Cesca points out that Hillary Clinton is behind in cash. "Obama can maintain his present clip for much longer and could potentially spend the Clintons into the ground," he writes.
05:15 GMT : California : Hillary Clinton and John McCain to win the state.
05:13 GMT : Missouri : John McCain to win the state.
05:11 GMT : Arizona : Hillary Clinton to win the state.
04:55 GMT : Hillary Clinton seems to have carried voters who make less than $15,000 a year, while Barack Obama attracted those who earn more, Democratic strategist Paul Begala tells CNN television.
04:49 GMT : California : ABC says data from the state suggests Clinton and McCain are ahead at the moment, but that it is still too close to call.
04:45 GMT : Chicago : Barack Obama tells an ecstatic crowd of supporters: "Our time has come, our movement is real and change is coming to America."
04:38 GMT : Phoenix : Arizona : John McCain says: "I think we must get used to the idea that we are the Republican Party front-runner for the presidency of the United States and I don't really mind it one bit." He congratulates Mike Huckabee and Mitt Romney on their primary wins.
04:37 GMT : Minnesota : Mitt Romney is projected to win the state.
04:26 GMT : ABC calls Idaho and Colorado for Barack Obama.
04:15 GMT : African-American Democratic voters opted overwhelmingly for Barack Obama in the seven Super Tuesday states with a significant African-American population, according to exit polls. He won at least 60% of the African-American vote in each of the states, with 94% backing him in his home state, Illinois.
04:08 GMT : Atlanta : Georgia : Barack Obama's supporters have been celebrating his victory, with one saying the campaign's "early investment in the state really paid dividends".
04:06 GMT : California : US networks say both the Democratic and Republican contests are too close to call to be able to predict winners based on exit polls in the state.
04:05 GMT : Arizona : John McCain is projected to win the state.
04:02 GMT : North Dakota : Mitt Romney is projected to win.
03:52 : New York : Hillary Clinton tells supporters: "After seven years of a president who listened only to the special interests, you're ready for a president who'll bring your values, your dreams and your voice to your White House."
03:44 GMT : Alabama : Mike Huckabee's victory in Alabama will please many of the voters in the state, who see faith as an important attribute for any presidential candidate, says the BBC's Rajini Vaidyanathan. "His values are very much in line with most of the faith-based Christians in America," says Richard Maust, a deacon from the Anniston Bible Church in Alabama.
03:42 GMT : Tennessee : Mike Huckabee projected to win the state, say reports.
03:39 GMT : Connecticut : Barack Obama projected to win the state.
03:34 GMT : Chicago : Illinois : It is an extraordinary night for Mike Huckabee and the Christian evangelical vote has clearly come out in force to back him, says the BBC's Katty Kay.
03:33 GMT : Boston : Mitt Romney tells supporters: "One thing's clear: this campaign's going on. I think there were some people who thought that it was all going to end tonight, but they're wrong; it's not going to end tonight."
03:21 GMT : Minnesota : Barack Obama projected to win the state.
03:20 GMT : Illinois : Chicago : The momentum is clearly with Barack Obama, says his supporter, Senator Dick Durbin.
03:09 : Little Rock : Arkansas : Mike Huckabee tells supporters: "We are still on our feet and much to the amazement of many we are getting there folks, we are getting there."
03:05 GMT : Phoenix : Arizona : A spokesman says John McCain is "cautiously optimistic", but adds that he "doesn't want to get too excited" yet.
03:04 GMT : Utah : Obama is projected to win Utah and North Dakota, say reports.
03:00 GMT : John McCain projected to win Oklahoma and Mitt Romney to win Utah.
02:53 GMT : Washington DC : Howard Dean, chairman of the Democrat National Convention, says a long nomination fight between Barack Obama and Hillary Clinton will help his party. He tells the BBC: "There's huge enthusiasm and the more people see of the candidates, the more enthusiastic they will get about them."
02:47 GMT : Little Rock : Arkansas : Huckabee campaign manager Chip Saltsman tells ABC: "Romney keeps talking about how this is a two-man race. We agree with him. And the two men are John McCain and Mike Huckabee."
02:25 GMT : Illinois : Chicago : Barack Obama's projected win in Kansas is an interesting insight into how he can do among more conservative Democrats, says the BBC's Katty Kay.
02:27 GMT : Alabama : Barack Obama to win the state. Political analyst Rick Klein tells ABC News it would be another decent-sized southern state in Mr Obama's column, and another indication that Democratic voters are split.
02:18 GMT : John McCain projected to win New York and Hillary Clinton to win New Jersey, say reports.
02:16 GMT : Little Rock : Arkansas : Mike Huckabee, who is also governor of Arkansas, sends his condolences to the families of the three people killed by bad weather in the state, adding: "Nothing is as important as the lives of these Arkansans."
02:09 GMT : New York : Projections of a Clinton win in Massachusetts are delighting her supporters who feared Senator Ted Kennedy's Obama endorsement would swing that state for the Illinois senator, says the BBC's Laura Trevelyan.
02:05 GMT : Delaware : Barack Obama to win, say reports.
02:03 GMT : New York : The mood among the Clinton camp is ebullient and has completely transformed, says the BBC's Gavin Hewitt. The indications are Hillary Clinton's support among women voters is holding up, he adds.
02:01 GMT : Hillary Clinton to win New York and Massachusetts, say reports.
01:50 GMT : "The McCain / Huckabee collusion is a major story tonight," reports Marc Ambinder on his Atlantic magazine blog. "Huckabee's victories are likely to put enormous pressure on the well-funded Romney to drop out."
01:44 GMT : Alabama : Huckabee is projected to win the state.
01:39 GMT : Delaware : John McCain is projected to win the state.
01:32 GMT : New York : The Clinton camp on its projected wins in Arkansas and Tennessee: "For months, the Obama campaign has been spinning that they have a monopoly on red states; tonight we showed that they don't. With these first two victories, Hillary Clinton has demonstrated that she can compete and win in red states."
01:30 GMT : Arkansas : Polling closes. ABC predicts Hillary Clinton to win for the Democrats and Mike Huckabee to take the Republican contest.
01:21 GMT : Tennessee : Hillary Clinton is projected to win, say reports.
01:09 GMT : New York : As the news comes that Mrs Clinton has won Oklahoma - and her rival Barack Obama has taken Illinois - the BBC's Gavin Hewitt says the feeling in the Clinton camp is that it is going to be a mixed night of results.
01:07 GMT : Illinois : Chicago : The BBC's Katty Kay says the impression in the Obama camp is that the night is going well so far.
01:01 GMT : John McCain is projected to win Connecticut, Illinois and New Jersey, says the BBC's Louisa Brooke. She says Mitt Romney is projected to take his home state of Massachusetts.
00:40 GMT : Washington DC : Georgia was one of the most predictable Super Tuesday states for Barack Obama, who had a lead in every recent poll there by a wide margin, University of Virginia politics expert Larry Sabato tells the BBC.
00:33 GMT : New York : Doug Hattaway of the Clinton campaign is downplaying expectations and tells the BBC's Laura Trevelyan it would be a shocker if the former first lady lost here.
00:25 GMT : It looks like Mr Obama took 43% of white voters in Georgia, compared with 24% in South Carolina a week and a half ago, political correspondent Rick Klein tells ABC News. He says the big concern after South Carolina was that Mr Obama had become the "black" candidate but that Georgia's initial results suggest this is not the case.
00:20 GMT: New Haven : Connecticut : Hillary Clinton's daughter Chelsea has been cautioned for serving cups of coffee to election workers, Newsday reports. State law bans politicking within 75ft of a polling station.
00:15 GMT : Georgia : ABC exit polls suggest Barack Obama has won 86% of the black vote in the Democratic primary, with Hillary Clinton on 13%. This would be a wider margin than in last month's South Carolina primary.
00:08 GMT : Boston : Mitt Romney is "hoping to stay alive" in his battle with John McCain for the Republican nomination, the BBC's Kim Ghattas reports. There is a feeling Mr Romney might beat Mr McCain in California, she adds.
00:01 GMT : Georgia : Obama is projected to win the state, say reports.
23:25 GMT : Washington DC: BBC North America editor Justin Webb says that if one clear front-runner comes out of the Republican contest and the party rallies behind him, as is traditionally the case, it may put pressure on the Democrats to do the same.
23:20 GMT: Arizona : Phoenix : There is optimism bordering on confidence in the John McCain camp, says the BBC's David Willis.
23:10 GMT : Chicago : African-American turnout is said to be up on previous years at an inner-city Chicago voting station, according to the BBC's Michael Buchanan. One undecided Democratic voter put the names of Mr Obama and Mrs Clinton in a hat and voted for the one that came out. But she would not say which one.
22:47 GMT : Barack Obama is in the lead among black voters and
Hillary Clinton among Hispanic voters in Democratic primaries, according to exit polling by the Associated Press.
22:36 GMT : Georgia : Atlanta : Hillary Clinton will have a "very good day in Georgia if we poll within five or seven points" of Barack Obama, volunteer Tina Ward-Pugh tells the BBC's Rajini Vaidyanathan.
21:40 GMT: Washington : Mike Huckabee's win in West Virginia should be considered an upset that has hurt Mr Romney, says the Washington Post's political blogger Chris Cillizza.
20:40 GMT : The BBC's Kim Ghattas says the loss of West Virginia is bound to upset Mitt Romney, who was hoping he would come on top in this winner-takes-all state. Huckabee won by only a five-point difference but that was enough to take all 18 delegates. One explanation is that supporters of John McCain, who once led in the state, went over to Huckabee to stop a Romney win.
20:20 GMT : Atlanta, Georgia : Officials tell the BBC's Rajini Vaidyanathan that turn-out has been heavy so far. They are putting the increase down to heightened interest in the nomination races in both parties.
20:15 GMT : Washington : ABC's political correspondent Sam Donaldson tells the BBC that while Mr Obama may have mobilised the young and the independents, there are many states where he will not be able to rely on them. Until now, he says, Mr Obama's momentum has been like a tsunami. But even they tend to recede, he adds.
20:06 GMT : Washington : The BBC's Adam Brookes says Mr Huckabee's West Virginia win is "somewhat surprising". He says: "He seems to command the loyalty of a fairly narrow slice of the Republican party - the evangelicals. He is not expected to duplicate that in larger states."
19:50 GMT : Illinois : Barack Obama tells reporters that as far as he is concerned, Mrs Clinton is still the favourite.
19:49 GMT : Chicago : The BBC's Michael Buchanan says: "This is Barack Obama's home state and the latest polls show he has a huge lead over Hillary Clinton, as does John McCain over Mitt Romney. But temperatures here are plummeting and voters are being urged to come out early before a winter snow-storm kicks in this evening."
McCain leads the Republican race with double digits, polls say
19:24 GMT : West Virginia : Former Baptist minister Mike Huckabee wins the first contest of the day, picking up 18 delegates at a Republican nominating convention.
19:10 GMT : Union Square, New York : US political commentator Jeffrey Robinson tells the BBC not to discount Republican Mike Huckabee: "He's out of money but he still has the evangelical vote."
18:05 GMT : New York : ABC's Political Director David Chalian tells the BBC that the race for the Democratic nomination is "neck-and-neck. Polls are showing a slight lead for Hillary but within the margin of error".
17:40 GMT : Washington : Hillary Clinton's campaign team tell the BBC's Adam Brookes that they made some 12 million phone calls on Monday to convince people to vote for her.
17:00 GMT : The Atlantic's blogger Andrew Sullivan writes: "McCain's emergence will either forge a new Republican foreign policy consensus, or blow the whole apparatus apart."
16:30 GMT : US voters abroad have been going to special polling stations at 76 locations in 33 countries set up by Democrats Abroad. Sara Sundelius, a Stockholm resident with dual
American and Swedish citizenship, said she voted for Hillary Clinton: "I think she seems more experienced in foreign policy." Republicans Abroad does not have an official primary.
16:10 GMT : New York : Reader Kim B says she is getting ready to go and vote: "There is so much at stake this coming election - it makes you feel a little tense and edgy to think about it. The weather here right now reflects that - it is actually storming outside - lightening and thunder in February!"
HAVE YOUR SAY
I believe that Senator McCain has the right solutions for this country. The election is important for this country because it might go either way
Jesus G Arredondo, Texas
15:55 GMT : Atlanta, Georgia : The BBC's Rajini Vaidyanathan says: "For the first time in a major election here, everyone who wants to vote has to have photo ID with them if they vote in person. Reports suggest that early voting here has gone up. Some here are predicting turnout could even double this time round."
15:40 GMT : Harlem, New York :
The BBC's Gavin Hewitt says: "We went to a polling station just around the corner from where President Bill Clinton had set up the headquarters for his global foundation.
Even among the early voters, there were indications of strong support for Barack Obama.
One young African-American woman called Katrina said she was voting for Obama and the Clintons belonged to the past. It seems that Hillary Clinton still has good support amongst older African-Americans who remember the Clinton years."
This polling day has seen some of the highest levels of voter turn-out
15:25 GMT : West Virginia : Addressing the crowd, Mitt Romney says that these are "critical times for our nation". Underlining his conservative credentials, he tells his supporters: "You can choose between a Republican in the White House - the house that Ronald Reagan built - or we can take a left turn for the party."
14:45 GMT : Washington : The BBC's Justin Webb says a win for John McCain would be a "knock-out blow" which could transform the Republican party, putting a man convinced of the perils of climate change at its head.
14:33 GMT : Paris : A US Democrat voter in the French capital tells the BBC that the "senator from Illinois" - Barack Obama - will get her vote.
"Today, I think that we are going to have a big change in America and I feel it, I'm inspired by the man and I express it today in the alchemy of the democratic process."
14:03 GMT : New York : Democratic hopeful Hillary Clinton casts her vote in Westchester County. Accompanied by her husband and former President Bill and her daughter Chelsea she describes the experience as "humbling and overwhelming". She tells reporters: "Obviously there is a lot at stake, the stakes are huge for our country, lots of big challenges, but America is up to it."
13:40 GMT : New York : Republican front-runner John McCain is on the stump in New York City, telling a small crowd at the Rockefeller Plaza that he is feeling confident. "We're going to win today, we're going to win the nomination and
we're going to win the presidency."
12:07 GMT : London : Reader Nanci Hogan tells the BBC by e-mail: "I just voted for Obama in the Global Democratic Primary by e-mail. Expatriate Americans can vote today and we get 22 delegates! Get out and vote y'all!"
11:22 GMT : New York : One of the first voters to emerge from a New York City polling station says he voted for Mr Obama: "For so many reasons. I think Hillary has so much baggage, I want a black president whose middle name is Hussein and he seems like a great guy," Stuart Bernstein, a 47-year-old literary agent tells the Associated Press news agency.
11:00 GMT : Voting begins in the US states of Connecticut, New York and New Jersey. New York, one of the most populous states, will be closely watched as it offers the second highest number of delegates for both parties in today's contest. Democrats abroad have already begun to cast their vote, in polling stations and online from Thailand to Spain.