ABC News' Christine Byun Reports: Republican candidate Fred Thompson said his rivals should "quit whining" about his recent endorsement from the anti-abortion group, National Right to Life Committee.
"They probably ought to quit whining about it and tearing down the people whose endorsement they said a few days ago they desperately wanted," he said.
Thompson hit back at a comment made by an influential supporter of his GOP rival, former Gov. Mitt Romney, R-Mass.
Paul M. Weyrich, president of the Free Congress Foundation and a Romney supporter, slammed the endorsement this week, arguing it "makes no sense," and speculated it was motivated by money.
"I think in all probability the Thompson people were engaged with the National Right to Life people in financial dealing," Weyrich told the Washington Times newspaper.
Thompson hit back at the comments Thursday.
"It's so ridiculous I wouldn't label the [Mitt Romney] campaign with that," he said.
Thompson said Romney's campaign "worked very, very hard for that endorsement, and you know, did all that they could and lost."
ABC News' Matt Stuart contributed to this report.