Susan Walsh/AP Photo

MAUMEE, OHIO - At the kick-off rally for President Obama' first campaign bus tour of the election season, former Ohio Governor Ted Strickland, a co-chair of the Obama 2012 campaign, assailed presumptive GOP nominee Mitt Romney's off-shore accounts.

"Oh, what a contrast, my friends, between these two men who would be president!" Strickland said, standing outside the Wolcott House Museum. "President Obama is betting on America and American workers, and Mitt Romney is betting his resources in the Cayman Islands, in Bermuda, in Switzerland and God only knows where else he is putting his resources."

Strickland was referring to Vanity Fair and Associated Press investigations into perfectly legal - but politically controversial - off shore accounts Romney has held. The articles speculate - but do not state or prove - that these accounts may have been set up in apparent efforts to avoid paying U.S. taxes, though Romney has denied such offshore manipulations. Romney had not disclosed some of these accounts in previous public filings.

"Think about it, think of this, a man who wants to be the president of the United States took his great wealth, and instead of investing that great wealth in America, the country he hopes to lead, he somehow chose to find the tax haven, Switzerland, where he opened up a bank account," Strickland said. "He invested in the Cayman islands, has a corporation in Bermuda, and he took money from shadowy south American investors when he started Bain Capital and now my friends, he conveniently has decided that he will not release his income tax returns. Doesn't it make you wonder what Mitt Romney is trying to hide from the American people?"

The Obama campaign earlier today released a web video assailing Romney on this issue, with senior campaign officials emailing and tweeting the stories to reporters as if they had side gigs doing PR for Conde Nast and the AP.

"President Obama is the in-sourcer of jobs and Mitt Romney is the outsourcer of jobs," Strickland added, referring to a June 21 Washington Post report suggesting the private equity firm Romney once helmed was an innovator in the technique of sending jobs overseas - a story the Romney campaign hotly disputes.

In a statement, Romney campaign spokeswoman Amanda Henneberg said, "President Obama once said, 'If you don't have a record to run on, then you paint your opponent as someone people should run from. You make a big election about small things.' Now it's President Obama who doesn't have a record to run on, so he and his campaign have resorted to false and ridiculous attacks. His policies have failed to fix the economy and create jobs for the middle class. Mitt Romney has the record and plan to create jobs and turn around the economy."

(You can read the Post's ombudsman's account on the dispute HERE. His basic conclusion: "Romney may not have done anything personally to ship U.S. jobs overseas before he left Bain in 1999, and the offshoring trend did accelerate after he left. But Bain knowingly and far-sightedly made strategic investments, with Romney at the helm, in these pioneering outsourcing firms in the late 1990s, which grew into some of the largest outsourcing and offshoring companies in the world. And Romney and Bain shared in their profits while he was chief executive and after he left.")

-Jake Tapper and Mary Bruce

Get more pure politics at ABC News.com/Politics and a lighter take on the news at OTUSNews.com

* This article has been updated with some clarifying language describing the Vanity Fair and Associated Press stories.