Mitt Romney raises millions in the Hamptons CAMPAIGN 2012

David Intrator plays the saxophone as protestors from MoveOn.org, the Occupy Movement and the Long Island Progressive demonstrate against a fundraiser for Republican presidential candidate Mitt Romney on the beach in front of the home of industrial billionaire David H. Koch on Sunday, July 8, 2012, in Southampton, N.Y. Romney would be among the nation's richest presidents if elected. He made his fortune at Bain Capital, a Boston-based private equity. (AP Photo/Kathy Kmonicek) less David Intrator plays the saxophone as protestors from MoveOn.org, the Occupy Movement and the Long Island Progressive demonstrate against a fundraiser for Republican presidential candidate Mitt Romney on the ... more Photo: Kathy Kmonicek, Associated Press Photo: Kathy Kmonicek, Associated Press Image 1 of / 1 Caption Close Mitt Romney raises millions in the Hamptons 1 / 1 Back to Gallery

Southampton, N.Y. --

Mitt Romney privately raised millions of dollars from New York's elite on Sunday, as Democrats launched coordinated attacks against the presumptive Republican presidential contender, intensifying calls for him to explain offshore bank accounts and release several years of tax returns.

The line of attack, dismissed by the Romney campaign as an "unfounded character assault," follows new reports that raise questions about Romney's personal wealth, which could exceed $250 million. President Obama's re-election campaign is expected to push the strategy throughout the coming week, portraying Romney as disconnected from the middle-class voters he needs to win the presidency.

"He's the first and only candidate for the president of the United States with a Swiss bank account, with tax shelters, with tax avoidance schemes that involve so many foreign countries," Sen. Dick Durbin, D-Ill., said on CBS' "Face the Nation." He's one of several high-profile Democrats who spoke out on the Sunday morning news shows.

Romney may have unintentionally helped the Obama campaign.

Republican donors driving Mercedes, Bentleys - and, in one case, a candy red 2013 Ferrari Spider - crowded into a series of closed-door Romney fundraisers in the Hamptons on Long Island's South Shore. Wall Street bankers and brokerage house chiefs, among others, make the area their weekend playground.

"I think he's a plain-talking guy," said Peter Cohen, the former Shearson Lehman Bros. chief who now heads his own investment banking firm, as he chewed a cigar in his black Range Rover outside a Romney fundraiser expected to generate $3 million.

Romney's day concluded at the Southampton estate of billionaire industrialist David Koch, where donors were asked to give $50,000 per person or $75,000 per couple.