Hillary Clinton thanks Puerto Ricans for their support
Hillary Clinton has said her fight for the Democratic presidential nomination will go on, after winning a largely symbolic victory in Puerto Rico.
With only two state contests left to fight, she is trailing Barack Obama by 1,915 delegate votes to 2,071, according to AP's rolling count.
She insisted she was the best candidate to fight the Republicans in November.
Her campaign earlier suffered a setback when the party compromised over contest results from Florida and Michigan.
But her campaign hopes that the victory in Puerto Rico could help Senator Clinton convince more so-called super-delegates - party officials, with a free choice over which candidate to support - to back her presidential bid.
Total delegates: Obama, 2,071; Clinton, 1,915
Super-delegates: Obama, 333; Clinton, 290
Winner needs 2,118 delegates
Puerto Rico's elected delegates: Clinton, 38; Obama 17
South Dakota and Montana have 31 elected delegates between them
The final two Democratic nominating contests - Montana and South Dakota - will be held on Tuesday.
Puerto Rico, a territory associated with the US, sends 55 pledged delegates to the Democratic Party's national convention in August, although its people will not have a vote in the actual presidential election.
Mrs Clinton took 38 of them to Senator Obama's 17, according to the Associated Press. Mrs Clinton also won four of the territory's unelected super-delegates to her rival's two.
Speaking to her cheering supporters after her win, she argued that because the race was so close, it was the senior members of the Democratic Party who would have to decide.
It's coming down to the last hold-outs, the desperate crowd
She said they would have to answer three questions in deciding on the presidential nominee.
"Which candidate best represents the will of the people who voted in this historic primary, which candidate is best able to lead us to victory in November and which candidate is best able to lead our nation as our president in the face of unprecedented challenges at home and abroad?" she asked.
A spokesman for Mr Obama said he hoped to clinch the nomination this week, after the last two primaries.
He needs to win at least 2,118 delegates to succeed.
'Right to appeal'
Mrs Clinton's supporters have said they reserve the right to appeal against Saturday's Democratic Party committee ruling that restored some of the votes for her from Florida and Michigan.
Barack Obama was campaigning in South Dakota on Sunday
Mrs Clinton won both states, but both were initially discounted because they held their primaries in January, in contravention of party rules.
Neither candidate campaigned in the contests, and in Michigan, Mr Obama's name was not even on the ballot.
Mrs Clinton wanted the committee to allow delegates from Florida and Michigan to vote at the convention in August.
Delegates to that convention, chosen in primary contests in each state, will decide which politician becomes the Democratic Party candidate in November's presidential election.
The compromise gives Mrs Clinton 69 delegates in Michigan, compared to Mr Obama's 59. And in Florida, she gains 105 delegates to Mr Obama's 67.
This reduces Mr Obama's lead - previously 202 - by 48, but the delegates from Michigan and Florida will only have half a vote each, so her gains are reduced.
But, barring appeals, Mr Obama's victory looks more certain than ever, says the BBC's Jamie Coomarasamy in Washington.
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