Washington (CNN) - The super PAC backing President Barack Obama, Priorities USA Action, has reserved $2.2 million in ad time in five key battleground states for commercials to run through September, according to a Republican media tracking source.
The group has bought $935,179 for broadcast and cable time in Colorado, Florida, Ohio, Pennsylvania and Virginia beginning Tuesday and running through next Monday.
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Separately, Priorities has reserved an additional $1.28 million for cable commercials in those same five states through September 3.
As part of its new buy, Priorities will go up with a 60-second spot attacking Mitt Romney on his business experience while he headed the private equity firm Bain Capital, according to a source close to the group.
The super PAC has been hitting Romney hard in recent weeks, including one 60-second commercial, for his Bain Capital connections by pointing out how some of the businesses the firm invested in later laid off employees.
Those actions mostly took place after Romney says he gave up his management of the company in February 1999. However Democrats are pointing to several filings Bain made to the Securities and Exchange Commission as well as documents from Romney himself after that point that they say prove he had control of the company until 2002.
The ad buy will bring Priorities' media total to $10.5 million.
But the Democrats' outside committees are being outspent and outraised by their Republican counterparts.
While Priorities said it brought in $6.1 million in June, the super PAC backing Romney, Restore Our Future, said it raised more than $20 million last month.
Also Restore Our Future has bought almost $7 million for ads in 11 states through the Olympics, which will bring its ad total since May to $18.3 million. Meanwhile, Crossroads GPS, the advocacy group founded by Karl Rove, is in the middle of a $25 million ad campaign running through early August that is hitting Obama over his economic policies. And American Crossroads, the super PAC also founded by Karl Rove, has pledged a fall media campaign of almost $40 million.
You can follow Kevin Bohn on Twitter @KevinBohnCNN
– CNN Political Editor Paul Steinhauser contributed to this story.