Democratic presidential candidate Barack Obama raised more than $150 million in September, a stunning and unprecedented eruption of political giving that has given him a wide spending advantage over rival John McCain.

The campaign released the figure on Sunday, one day before it must file a detailed report of its monthly finances with the Federal Election Commission.

Obama's money is fueling a vast campaign operation in an expanding field of competitive states. It also has underwritten a wave of both national and targeted video advertising unseen before in a presidential contest.

Campaign manager David Plouffe, in an e-mail to supporters Sunday morning, said the campaign had added 632,000 new donors in September, for a total of 3.1 million contributors to the campaign. He said the average donation was $86.