Obama wins Maine Democratic presidential contest

VIRGINIA BEACH, Virginia (Reuters) - Sen. Barack Obama won Maine's contest to choose a Democratic presidential candidate on Sunday, handing rival Hillary Clinton another defeat in their tight race to represent the party in the November election.

Sunday's win made a clean sweep for Obama, a senator from Illinois, of the states that have held nominating contests since "Super Tuesday", when more than 20 states had their say in choosing candidates to compete to succeed President George W. Bush.

Obama won Louisiana, Nebraska and Washington on Saturday, giving him a burst of momentum in a deadlocked race with Clinton, a senator from New York, where every delegate to the party's summer convention has become crucial.

"I want to thank the people of Maine," Obama told a crowd of some 18,000 in Virginia Beach, saying he had won contests from coast-to-coast. He was campaigning in Virginia ahead of its contest on Tuesday, when Washington D.C. and Maryland also hold elections.

Obama was projected to pick up 15 delegates in Maine compared to nine for Clinton, his campaign manager, David Plouffe said in a statement.

"Today, Obama won an upset victory in Maine, a state where internal and external polls had Clinton leading in the days leading up to the caucuses," Plouffe said.

Clinton and Obama have been about even in pledged delegates but well short of the 2,025 needed to win the Democratic nomination.

Democratic rules allocate delegates on a proportional basis statewide and in congressional districts, meaning even the loser in each state can win blocks of delegates.

(Reporting by Jeff Mason, editing by Philip Barbara)