President Obama raised $53 million last month for his reelection, a substantial increase from the month before.

In February, Obama raised $45 million from 348,000 donors. This month he upped his total by $8 million, and increased his donor pool to 567,000.

Campaign manager Jim Messina announced the total — raised in conjunction with the Democratic National Committee and two joint committees, the Obama Victory Fund and the Swing State Victory Fund — in a Web video that focused on small donors.

“People are building this organization five and 10 bucks at a time to take on Mitt Romney,” Messina said.

Romney, the former Massachusetts governor, who is all but certain to win the Republican nomination, has yet to release his March numbers. He raised $12 million in February. In early April he began fundraising jointly with the Republican National Committee, which will enable Romney to take in larger checks.

Ninety-seven percent of donations to Obama’s re-election effort were for $250 or less, the Obama campaign said. The average contribution was $50.78.

As of mid-March the president’s campaign had close to $85 million in cash on hand, according to FEC filings.