Pouncing on a new Washington Post report on certain Bain Capital investments, leaders in the American labor movement on Friday assaulted former Bain presumptive GOP presidential nominee Mitt Romney as a "happy outsourcer" willing to send American jobs overseas for personal gain.

The problems with the American economy, AFL-CIO President Richard Trumka asserted on a call with reporters, are "vulture capitalists and Wall Street and CEOs who put their own pay ahead of workers. Our problems are companies like Bain Capital and happy outsourcers like Mitt Romney."

Trumka was following a line of attack quickly taken by the Obama campaign, which branded Romney "outsourcer-in-chief" upon publication of the Post report. In the piece, reporter Tom Hamburger detailed how Bain, Romney's old private equity group, invested in firms that specialized in helping corporations move American jobs abroad to cheaper countries in Asia. Based on reports from the Securities and Exchange Commission, the piece said Bain owned firms that were "pioneers in the practice of shipping work from the United States to overseas call centers and factories making computer components."

On Friday, Trumka was joined by United Steelworkers President Leo Gerard and Communications Workers of America President Larry Cohen in assailing Romney for the investments. Both unions have suffered from the broader outsourcing trends of the past two decades.

Gerard called Romney a "hypocrite," given that the Republican staked his campaign on a record of job creation at Bain and as governor of Massachusetts.

"To run around the country and say the things he has said about job creation in America and not know that he would be found out as an outsourcing pioneer … it makes it very clear this is someone who can't be trusted," Gerard said.

"Equity firms like Bain are only about wealth creation. That's okay, but let's understand that's all they're about."

The Romney campaign did not immediately respond to the charges leveled by the union leaders, although Friday morning the campaign dismissed the Post report as "flawed." "This is a fundamentally flawed story that does not differentiate between domestic outsourcing versus offshoring nor versus work done overseas to support U.S. exports," campaign spokeswoman Andrea Saul said. "As president, [Romney] will implement policies that make it easier and more attractive for companies to create jobs here at home."

The outsourcing issue hits the campaign at a time when labor groups and some Democrats are pushing legislation that would curb sending American jobs offshore. Sen. Debbie Stabenow (D-Mich.) has introduced a bill that would give a tax break to companies that return jobs to the U.S. while taking away tax deductions for companies that move jobs abroad, similar to policy proposed earlier this year by Obama. The president has called for more job "insourcing," although American companies have continued to ramp up their overseas operations during his tenure.

The anti-outsourcing message could play well in states like Ohio that have been hurt badly by the loss of American manufacturing jobs, and Trumka said Friday that it will be one of the primary messages pushed by labor heading into the fall. But he also said labor will seize the outsourcing issue to push its policy objectives, such as addressing currency manipulation by overseas competitors, pushing for trade deals that "benefit workers and not just multinationals," and passing legislation that would punish U.S. companies that send their call service centers overseas.

"We're committed to defeating every last politician who thinks outsourcing American jobs is creative destruction," Trumka said.