Senator Hillary Clinton last night turned to Miami’s rap stars in a late flurry of campaign fundraising only hours before the first important deadline of the 2008 presidential race.

All declared candidates for the White House must today begin reporting to the Federal Election Commission how much money they raised in the first quarter of the year.

Despite a record succession of multi-million-dollar campaign events that are estimated to have netted Clinton up to $50m (£25.5m) in the past three months, the New York senator’s aides have been shaken by reports that her main Democratic rival, Senator Barack Obama, has been accumulating a formidable war chest of his own.

Obama is almost certain to finish a distant second when the fundraising totals are made public on April 15.

But the Illinois senator is known to have made significant progress among wealthy donors in Hollywood and New York who previously supported Clinton. He has also received money from at least 100,000 supporters online.

In an attempt to secure her lead in what all sides describe as “the money primary”, Clinton raised $1m in New York on Friday and then headed for Miami, where the rapper Timbaland was hosting a cocktail party for guests who paid more than $2,000 to attend.

The Clintons were also expected at a second event likely to raise another $100,000.

The money battle between the two leading Democrats has left all other candidates trailing.

Neither Rudolph Giuliani nor John McCain, the two leading Republicans, is likely to overtake either Clinton or Obama, who may have raised more than $20m so far.

The main weapon in Clinton’s formidable fundraising arsenal has been her husband Bill, who has been widely deployed around the country to wring money out of prospective donors and to talk them out of being seduced by Obama’s comparative youth and glamour.

The ex-president was reported yesterday to have attended 16 fundraisers in the past six weeks, far more than many Democrats expected.

All the campaigns have been playing down reports about how much they have raised, in the hope of surpassing expectations when the first quarter results are announced.

McCain’s team admitted it had got off to a “late start” in raising money, and Giuliani is expected to confirm his status as the Republican frontrunner by a wide margin.

The candidate with the most to lose in the money race is John Edwards, the former senator who needs a robust showing to persuade Democratic donors that he is still a viable candidate despite his wife’s battle with cancer. Potential donors are unlikely to support him if they think he may drop out of the race.

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