* Akin asks for forgiveness in Web ad
* Poll shows Akin still slightly ahead of Democrat McCaskill
WASHINGTON, Aug 21 (Reuters) - Republican Representative Todd Akin resisted pressure to quit the U.S. Senate race in Missouri on Tuesday, releasing a new ad apologizing for his inflammatory remarks about rape that have reinserted controversial abortion politics into the U.S. presidential campaign.
In an ad released online, Akin again apologized for his comments Sunday, when he claimed in a television interview that women could not get pregnant from "legitimate rape," even as senior Republicans condemned his remarks and called for him to step aside in the race.
"Rape is an evil act. I used the wrong words in the wrong way, and for that I apologize," Akin said in the spot.
"The 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," he added. Akin, noting that he is the father of two daughters, also said he wanted "tough justice" for rapists and expressed compassion for victims.
The Republican challenger is running against Democratic Senator Claire McCaskill in the Nov. 6 election. Tuesday is the last day for candidates to file in the Missouri race, giving Republicans until later in the day to submit a replacement, if Akin decides to drop out.
His comments have become a distraction ahead of the Republican convention next week to nominate Mitt Romney for U.S. president.
His comments have put the focus on social issues rather than Romney's main message of the economy and jobs. They also complicated Republican efforts to win the majority in the 100-member Senate.
But a poll late Monday night showed little effect from the controversy on the closely contested Missouri race.
Findings from Public Policy Polling showed Akin ahead of McCaskill 44 percent to 43 percent, even though the majority of Missouri voters said his rape comments were inappropriate. Before the controversy, the polling firm found Akin ahead 45 percent to 44 percent.
On Sunday, Akin told KTVI television in St. Louis that the need for abortions in the case of rape was a tough question and that as far as pregnancy is concerned, "if it's a legitimate rape, the female body has ways to try to shut that whole thing down."
Romney on Monday denounced Akin's remarks as "insulting, inexcusable, and, frankly wrong," and top Republicans have called on Akin to withdraw from the race and cut off advertising.
President Barack Obama and other Democrats also called Akin's remarks offensive.