Barack 10 points ahead nationally

Barack Obama is leading Hillary Clinton by 10 points nationally for the first time in the campaign, according to a new Gallup tracking poll which puts nationwide Democratic support for Obama at 52 per cent against Clinton's 42 per cent. The last time either candidate was ahead by double digits was in early February - when it was Clinton who was ahead by 11 points.

However, Clinton remains the frontrunner in Pennsylvania, where the next state primary is due to be held on April 22, and she told the Washington Post on Sunday that she is not going to bow to pressure to pull out. "I know there are some people who want to shut this down and I think they are wrong," she said. "I have no intention of stopping until we finish what we started and until we see what happens in the next 10 contests."

Meanwhile, Obama has won a second important endorsement in a matter of days from a fellow Democrat serving in the Senate alongside him and Clinton. Senator Amy Klobuchar of Minnesota says Obama "has inspired an enthusiasm and idealism that we have not seen in this country in a long time." Her backing followed that of Sen Bob Casey of Pennsylvania who used much the same language when he declared his allegiance to Obama on Friday and went out campaigning with him.

LAST UPDATED 12:55 PM, MARCH 31, 2008