US President Barack Obama's re-election campaign and its Democratic allies raised more than $45 million in February, increasing their financial haul compared to January as worries mount that Republicans could outspend Democrats in 2012.     

In a statement released on Twitter, Obama's campaign said 348,000 people contributed last month and 105,000 people gave money for the first time.     

Nearly 98 per cent of the month's contributions were $250 or less, it said.     

"Since April 2011, a total of 1.64 million people have pitched into own a piece of this campaign," the Twitter message said. Obama's Chicago-based re-election effort has spent the last several months building up a grassroots effort it hopes will help turn out the vote on Election Day in November.      

Obama's campaign, the Democratic National Committee, and other joint fundraising committees raised a combined $29.1 million in January.     

Campaign officials are concerned that outside groups known as Super PACs could outspend Obama in their quest to put a Republican in the White House.     

Super PACs are political groups that can raise and spend unlimited amounts of money to influence political campaigns.     

Obama held a five-event fundraising spree on Friday in Chicago and Atlanta, where he was projected to raise nearly $5 million or more.     

The president is his campaign's best fundraising draw, and Obama has done roughly twice as many fundraisers at this point in his re-election effort as his predecessor, Republican President George W Bush, had done at the comparable time.      

Obama has utilied the drawn-out Republican primary race to focus on boosting his campaign's coffers.

Though his campaign had $750 million in 2008, it is concerned that the same amount would not be sufficient this year to counter the onslaught of ads from the Republican opposition.     

The Super PAC supporting Obama, Priorities USA Action, raised just $2 million in January, significantly less than comparable amounts raised by Republican-leaning groups. – Reuters