Washington: What has come as a major setback for the US President Barack Obama when a key contributor for his re-election campaign has been accused of defrauding a businessman and impersonating a bank official.

Donor Abake Assongba gave more than USD 50,000 to Obama during the current election season. But her past legal troubles which include unpaid debts are creating a new headache for Obama's campaign.

The allegations were first reported on Sunday. A report says Assongba tried to rip off more than USD 650,000 from a Swiss businessman and use the funds to build a multimillion-dollar house in Florida.

A campaign spokesman declined to make any comment but told that it reviews issues involving questionable donors. Obama's campaign returned USD 200,000 last month to two men whose brother was a Mexican fugitive wanted by federal authorities.