US President Barack Obama, renowned as a champion fundraiser who piled up $750 million in 2008, warned supporters he would be outspent by his foe Mitt Romney in this year’s election.

The president lashed the Republican for huddling last weekend at a “secretive retreat” for rich donors and chiefs of fundraising committees targeting Democrats, portraying his policies as harmful to the middle class.

“I will be the first president in modern history to be outspent in his re-election campaign, if things continue as they have so far,” said Obama in a fundraising email sent out to his supporters.

“We can be outspent and still win — but we can’t be outspent 10 to 1 and still win.”

Obama’s email came as he wound up a two-day campaign and fundraising swing through New Hampshire, Massachusetts, Georgia and Florida, reportedly set to raise up to $5 million dollars for his election war chest.

In one event on Tuesday, Obama appeared in the plush Miami beach residence of a telecommunications executive and his wife, as around 30 guests chowed down on cuisine from a top chef after paying $40,000 per head to attend.