A Democratic fundraising group with ties to President Barack Obama has launched its first television ad, attacking Republican Mitt Romney.
The ad by Priorities USA will run in South Carolina, a key early primary state where Romney will campaign this weekend. The former Massachusetts governor is competing for the GOP nomination to challenge Obama in 2012.
Priorities USA was founded by two former top aides in the Obama White House.
The ad criticizes Romney for supporting a House GOP budget plan that would privatize Medicare for future retirees. It also says he shifts positions on key issues.
A Romney spokeswoman said the ad is part of a "smear campaign" and shows Democrats are trying to shift attention away from high unemployment in South Carolina and nationally.