Obama reveals fresh donation haul

The Obama campaign said it was amassing a "grassroots army"

The campaign of Democratic presidential hopeful Barack Obama has announced another sizeable haul of donations ahead of a key vote in Pennsylvania.

Mr Obama raised $40m (£20m) in March after taking a record $55m in February.

The campaign of his Democratic rival, Hillary Clinton, admitted it had been outraised but said it had enough funds to compete.

Mrs Clinton is hoping to peg back Mr Obama's lead when Pennsylvania holds its primary election on 22 April.

The latest count of pledged delegates to the National Convention in August, according to Associated Press, puts Mr Obama at 1,634 and Mrs Clinton at 1,500.

A total of 2,024 is needed to win the Democratic nomination.

Senator John McCain has already sewn up the Republican nomination and will fight the presidential election in November.

Analysts say the presidential campaign is shaping up to become the first billion-dollar US election.

McCain task

The key upcoming votes for the Democrats are Pennsylvania, with 158 delegates up for grabs, and North Carolina and Indiana in May.

The Obama campaign says it is relying heavily on small donors, with 442,000 contributing in March.

BARACK OBAMA: 1,634 States won: 25 HILLARY CLINTON: 1,500 States won: 16 Delegates needed to secure nomination: 2,024 Source: Associated Press, as of 3 April

Campaign manager David Plouffe said: "Many of our contributors are volunteering for the campaign, making our campaign the largest grassroots army in recent political history."

Clinton campaign communications chief Howard Wolfson admitted Mr Obama had "outraised us over the last several months".

But he said: "I would remind everyone that he outspent us over two to one on television in Ohio and Texas... we were able to win despite being outspent."

The Clinton campaign will not reveal its March donations take until the deadline of 20 April.

A new telephone opinion poll by Quinnipiac University suggested Mrs Clinton held a nine-point lead over Mr Obama in Pennsylvania, down from 12 points two weeks before.

Neither candidate can secure the 2,024 delegates needed by winning the remaining primaries alone, analysts say, and will need the votes of so-called super-delegates who are not bound by pledges.

Mr McCain meanwhile has said he is pressing on with his task of finding a vice-presidential running mate.

"I'd like to get it done as early as possible. I'm aware of enhanced importance of this issue given my age," the 71-year-old Arizona senator said.