Election officials in the Democratic Republic of Congo are counting the votes from one of Africa's most significant elections for many years.
The counting process is very slow and careful
Voting was mostly peaceful but a drunken soldier shot dead two election workers on Monday, sparking riots.
At least one person died in protests over alleged fraud in the north-east.
Congolese hope the election will end years of conflict and abuse of power. President Joseph Kabila faced ex-rebel Jean-Pierre Bemba in a run-off.
Results are not expected to be announced for about a week.
Sunday's run-off concludes DR Congo's first fully democratic polls since independence in 1960 and is supposed to draw a line under a five-year conflict.
The election officials were killed in the north-eastern town of Fataki in Ituri district, which remains one of the most unstable parts of DR Congo.
The soldier has been arrested, UN officials say.
Following the shootings, local people attacked some 43 polling stations and burnt the ballot papers, reports Reuters news agency.
There were some 50,000 polling stations spread across DR Congo, which is two-thirds the size of Western Europe.
Many Congolese fear that whoever loses the elections will resort to violence, as both men have considerable numbers of armed men and weapons at their disposal.
Both men have said they will accept the results, as long as they are free and fair.
The BBC's Mark Doyle in the capital, Kinshasa, says the short-term period, especially the announcement of the results, is going to be very dangerous.
British election observer and MP Judy Mallaber told the BBC's Network Africa programme that the polls had been "very well organised" in the eastern region of Maniema where she had been.
She said that she had been "very impressed" with the counting process, which was being watched by representatives of all political parties.
She said the count was taking a long time because officials were being so careful to make sure it was transparent.
Turn-out is reported to be lower across the country than in July's first round.
"From now on, leaders will rule for the people, not just possess power forever," Theoneste Mpatse-Mugabo told the AP news agency in the eastern city of Goma.
Voting was extended for several hours in the capital, Kinshasa, and other western areas because of delays following a violent thunderstorm in the morning, which turned streets into rivers.
In the north-eastern town of Bumba, supporters of Mr Bemba on Sunday burnt ballot boxes, after claims of vote-rigging, leading police to open fire, killing at least one person.
Shots were also fired at a polling station in Kinshasa following claims of attempted fraud.
Our correspondent says it is impossible to exaggerate how the destiny of DR Congo could shape the future of Africa.
Nine states border the country and all were affected by the wars caused by the long lack of real government in DR Congo, the power vacuum at the heart of Africa, he says.
Some four million people are thought to have died.
FIRST ROUND RESULTS
DR CONGO WAR
1998 - 2002
At least 8 armies, many rebel groups
2003: Rebels join unity government
East remains unstable
17,000 UN peacekeepers
Its rich reserves of minerals such as gold, diamonds and coltan - used in mobile phones - have attracted a series of armed groups, both Congolese and foreign, intent on looting.
UN officials say the polls are the most important on the continent since the 1994 election that ended apartheid in South Africa.
Mr Kabila has strong support in the east of Congo; Mr Bemba is popular in the west.
Many easterners credit Mr Kabila with ending the war and blame the conflict on rebels such as Mr Bemba.
Those in the west say Mr Kabila, who grew up in Tanzania, is not a true Congolese, unlike Mr Bemba.
Mr Kabila won first round polls on 30 July, but fell just short of the 50% needed for outright victory.
He has also gained the support of the candidates who came third and fourth - veteran nationalist Antoine Gizenga and Nzanga Mobutu, son of the country's long-time leader, Mobutu Sese Seko.
Extra UN peacekeeping troops are on standby in the east of the country.
In Kinshasa, the UN is being backed up by a special European Union military force.