President Obama's re-election effort raised $71 million dollars in June, substantially less than the monthly haul by GOP rival Mitt Romney, the Obama campaign has announced.

"June was our best fundraising month yet. We exceeded expectations - more than 706,000 people stepped up and pitched in for a grand total of $71 million raised for this campaign and the Democratic Party," wrote Obama for America chief operating officer Ann Marie Habershaw in an email to supporters.

"Bad news? We still got beat. Handily," she wrote. "Romney and the RNC pulled in a whopping $106 million."

June was Romney's best fundraising of the 2012 campaign, not counting sums raised by affiliated super PACs and outside groups. And while Obama's campaign aides had publicly anticipated being outraised, they jumped on the $35 million gap as reason to sound the alarm.

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"This is no joke. If we can't keep the money race close, it becomes that much harder to win in November," Habershaw said.

The Obama campaign says more than 2.4 million Americans have contributed to the president's re-election effort, including 181,000 giving for the first time in June. The average donation was $52.54, the campaign said.

President Obama hits the money trail again today, attending two closed-press, high-dollar events in D.C. expected to net more than $1.6 million.

Obama has already spent an unprecedented amount of time fundraising for an incumbent, attending 177 re-election fundraisers in his first term, including today's events.