BOSTON (June 26, 2012)--President Barack Obama was hauling in millions of dollars for his re-election bid Tuesday as he warned that Democrats will face a fundraising onslaught from Republicans during the fall campaign.

Mr. Obama collected more than $2.3 million at fundraisers Tuesday in Atlanta and Miami after top-dollar events Monday night in Boston.

Republican Mitt Romney raised more than $76 million last month for his presidential campaign and the Republican party, and Mr. Obama's advisers expect Republican-leaning super PACs to pull in $1.2 billion before the election, posing a big-money challenge for the president.

Mr. Obama told supporters Monday in New Hampshire that through November "the other side will spend more money than at any time in American history."