Rep. Todd Akin (R-Mo.) said on Monday that he is staying in the Missouri Senate race despite calls from prominent Republicans for him to resign the GOP nomination.

Akin appeared on a conservative talk radio show hosted by former Arkansas Gov. Mike Huckabee to apologize for his controversial comments on rape and assert that he would be staying in the race, saying that he hadn't yet received any calls to step down.

"No one has called me and said 'Todd, I think you should drop out,'" he said.

However, Sens. Scott Brown (R-Mass.) and Ron JohnsonRonald (Ron) Harold JohnsonGun proposal picks up GOP support GOP lawmaker to unveil bill banning gun bump stocks Senate Homeland Security chairman backs bump-stock ban after Las Vegas shootings MORE (R-Wis.) have publicly said Akin should step down as nominee.

"As a husband and father of two young women, I found Todd Akin's comments about women and rape outrageous, inappropriate and wrong. There is no place in our public discourse for this type of offensive thinking. Not only should he apologize, but I believe Rep. Akin's statement was so far out of bounds that he should resign the nomination for U.S. Senate in Missouri," Brown said in a statement.

And Johnson tweeted, "Todd Akin’s statements are reprehensible and inexcusable. He should step aside today for the good of the nation."

Akin's comments, that "the female body has ways to shut that whole thing down" if it's a "legitimate rape," sparked outrage from members of both parties on Sunday, with Republicans quickly distancing themselves from his statement and Democrats working to tie Akin to other Republicans. 

"I've really made a couple of serious mistakes here that were just wrong, and I need to apologize," he said in the interview. Akin had issued a statement attempting to clarify his statements, but until Monday afternoon hadn't apologized.

Akin went on to explain that rather than "legitimate rape," he meant "forcible rape," but he insisted that he understood that rape can lead to unwanted pregnancies and explained his mistake as a case of "foot-in-mouth disease."

"I don't know that I'm the only person in public office who suffered from a foot-in-mouth disease here," he said.

"I'm not a quitter ... I have not yet begun to fight," he said, shifting the conversation to the economy, which he says is the main reason he needs to stay in the race.

Sen. John CornynJohn CornynGun proposal picks up GOP support House bill set to reignite debate on warrantless surveillance Republicans jockey for position on immigration MORE (R-Texas), the chairman of the National Republican Senatorial Committee, released a carefully worded statement that neither called on Akin to resign nor offered him support.

“Congressman Akin’s statements were wrong, offensive, and indefensible. I recognize that this is a difficult time for him, but over the next twenty-four hours, Congressman Akin should carefully consider what is best for him, his family, the Republican Party, and the values that he cares about and has fought for throughout his career in public service," Cornyn said.

Sources confirm that Cornyn did speak with Akin and communicated that, were Akin to remain in the race, he would not only jeopardize Republicans' chances at taking the seat but also at taking back the majority in the Senate — and as such, the NRSC would not be investing a planned $5 million in the race, if Akin decided to remain.

Meanwhile, Republicans pressured Akin to drop out of the race.

A number of influential conservative voices, including Erick Erickson of the conservative blog RedState and GOP strategist Richard Grenell, tweeted out that Akin would be dropping out of the race Tuesday although that was seen as their way of pressuring the GOP nominee and not as a fact.

Senate Minority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellGun proposal picks up GOP support Children’s health-care bill faces new obstacles Dems see Trump as potential ally on gun reform MORE (R-Ky.) joined the chorus, issuing a statement that stopped just short of a call for resignation but did call Akin's comments "totally inexcusable."

"What he said is just flat wrong in addition to being wildly offensive to any victim of sexual abuse.  Although Representative Akin has apologized, I believe he should take time with his family to consider whether this statement will prevent him from effectively representing our party in this critical election," McConnell said.

The super-PAC Crossroads GPS, founded by influential GOP strategist Karl Rove, will be pulling the remaining funds they had reserved in Missouri, an undisclosed amount, but they've spent $5.4 million against Sen. Claire McCaskillClaire Conner McCaskillKoch-backed group targets red-state Dems on tax reform Overnight Cybersecurity: Equifax security employee left after breach | Lawmakers float bill to reform warrantless surveillance | Intel leaders keeping collusion probe open Las Vegas highlights Islamist terrorism is not America's greatest domestic threat MORE (D-Mo.) since 2011.

As the pressure increased, Akin tweeted: "I am in this race to win. We need a conservative Senate. Help me defeat Claire by donating" and included a link to a fundraising page.

The first deadline for Akin to withdraw from the race is 5 p.m. Tuesday. But Akin could also withdraw by court order on or before Sept. 25 — a deadline far enough away for the GOP to assess whether Akin still has a viable shot at the seat.

— Updated at 3:20 p.m.