Handout of US Representative Todd Akin in this undated official portrait provided courtesy of the House of Representatives. [Photo/Agencies]

WASHINGTON - US Congressman Todd Akin, under fire for controversial remarks on abortion and rape, insisted on Tuesday he would not leave the Missouri Senate race, despite pressure from fellow Republicans and talk of who might replace him on the Nov 6 ballot.

Akin - a staunch abortion opponent - vowed to stay in the contest against Democratic Senator Claire McCaskill, indicating he represents a conservative movement that must be heard.

A 5 pm local time (6 pm EDT) deadline passed with no indication he planned to take his name off the ballot.

Akin was defiant. His campaign posted a new web site on Tuesday seeking donations with a banner "I'm pro-life and I Stand with Todd Akin." It had briefly featured a picture of a fetus and a picture of McCaskill with US President Barack Obama, but the fetus image was later removed.

"We are going to continue in this race for US Senate," Akin told "The Mike Huckabee Show," a radio program hosted by the former Arkansas governor.

Republican presidential candidate Mitt Romney on Tuesday joined the chorus calling for him to pull out of his race after Akin claimed in a weekend television interview that it was extremely rare for women to get pregnant from "legitimate rape."

"Today, his fellow Missourians urged him to step aside, and I think he should accept their counsel and exit the Senate race," said Romney, who previously condemned Akin's comments.

The outrage over Akin's remarks sent waves of anxiety through the Republican Party a week before it reaches out to independent voters, especially women, at its national convention where it will nominate Romney to run against Obama.

Republicans fear the Akin episode could prevent them from winning in Missouri, lessening their chances of picking up the four seats they need ensure a majority in the 100-member Senate.

McCaskill had trailed Akin by about 10 points but a Public Policy Polling survey on Monday had Akin ahead by one point.

WHAT ABOUT JOBS?

To the dismay of many Republicans, Akin's woes have cast a spotlight on a part of the platform party members again endorsed on Tuesday: a call to oppose abortion with no mention of exceptions in cases of rape and incest.

That is not the position of Romney, who has said abortion should be allowed to end pregnancies resulting from rape or incest.

Obama, who supports abortion rights, also strongly denounced Akin's remarks, saying "rape is rape."

Romney's vice presidential running mate, US Representative Paul Ryan of Wisconsin, has expressed a harder line on abortion, saying it should be allowed only to save the life of the mother. The campaign said this week a Romney/Ryan administration would reflect Romney's position.

Ryan, who has co-sponsored anti-abortion legislation with Akin, called the Missouri candidate and suggested he think about leaving the Senate contest. "He thought I maybe should give some thought to stepping down, but he didn't tell me what to do. And that's because he's a very respectful and a very decent guy," Akin said on the Sean Hannity radio program.