The Obama campaign says a surrogate's use of the word "raping" to describe Mitt Romney's actions at his private-equity firm, Bain Capital, is inappropriate.

"I want to say to you: I don't take contributions from payday lenders. I refuse to do that," Rep. Jim Clyburn said on MSNBC this morning. "That's free enterprise. But there's something about that enterprise that I have a problem with. And there's something about raping companies and leaving them in debt and setting up Swiss bank accounts and corporate businesses in the Grand Caymans. I have a serious problem with that."

Patrick Devlin, a spokesman for Clyburn, said that the top-ranking Democrat used the word "raping" as a "synonym for rob or plunder."

Obama spokeswoman Lis Smith said in an email, "We strongly disagree with Congressman Clyburn's choice of words- they have no place in this conversation."

The private equity arena is the latest punching bag in the campaign. President Obama's latest ads focus on companies that Romney bought while at Bain, and which later went bankrupt while Romney made money off of them for his investors.