The US Democratic presidential candidate Barack Obama has overtaken his rival Hillary Clinton for the first time in endorsements from super-delegates.

Four super-delegates - party and elected officials - pledged to support Mr Obama, including two who previously supported Mrs Clinton.

Mr Obama also has a strong lead in delegates won in state primary and caucus votes.

The 800 super-delegates, party veterans and leaders, look set to decide who wins the nomination.

Senator Clinton has said that while the nominating race is not over, the Democrats will come together against the Republicans no matter who wins.

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