United States Republican presidential candidate Mitt Romney has called on embattled Republican congressman Todd Akin to withdraw from the race for a Senate seat in Missouri.
Mr Akin, who caused a national uproar by claiming women's bodies could prevent pregnancy in cases of rape, has so far refused to stand aside.
The 65-year-old congressman has instead asked to be forgiven for his remarks about "legitimate rape".
The BBC reports that in a campaign television advertisement he looks directly at the camera and says: "Rape is an evil act. I used the wrong words in the wrong way, and for that I apologise."
He adds: "Fact is, rape can lead to pregnancy. The truth is, rape has many victims. The mistake I made was in the words I said, not in the heart I hold. I ask for your forgiveness."
Mr Romney initially said Mr Akin's remarks were "offensive and wrong" but stopped short of urging him to drop out. Now he has joined one current and four former senators from Missouri in saying Mr Akin's candidacy does not serve the national interest.
Correspondents say Republicans fear the backlash to the remarks could endanger their campaign to win control of the Senate in the November elections.