Barack Obama is moving closer towards claiming the Democratic presidential nomination, despite losing the Puerto Rico primary to Hillary Clinton.

Sen. Clinton gained two-thirds of the vote and 38 delegates in Sunday's ballot, but according to independent delegate counts Sen. Obama has a strong lead.

The former first lady has confirmed her wish to stay in the nomination race until the Democratic party's summer convention.

Sen. Clinton told supporters she was more likely to defeat Republican nominee-elect John McCain in a general election.

"In the final assessment I ask you to consider these questions," the New York senator said.

 

"Which candidate best represents the will of the people who voted in this historic election?"

Sen. Clinton had won in both Michigan and Florida, but the results were scrapped after the states held their primaries early.

Barack Obama is expected to declare himself the winner of the contest whatever the result in tomorrow's primaries in Montana and South Dakota, the last of the campaign season.