A Republican nominee for the US Senate, who strongly opposes abortion rights, has denied a Daily Beast report that he paid for an abortion for a former girlfriend in 2009. Herschel Walker, a former American football player who is running for the US Senate in Georgia, called the accusation a “flat-out lie” and says he will sue the news outlet for defamation.

The Daily Beast published claims from a woman who says Walker paid for her abortion when they were dating. The woman, who was not named, claimed the allegation was supported by a receipt showing a $575 payment for the procedure, along with a get-well card, purportedly from Walker.

According to The Daily Beast, her bank deposit records show the image of a $700 personal check, purportedly from Walker, dated five days after the abortion receipt.

The woman claimed in The Daily Beast report that Walker encouraged her to end the pregnancy, saying that the time wasn’t right for a baby.

In a statement, Walker said he would file a lawsuit against the news outlet.

“This is a flat-out lie and I deny this in the strongest terms possible,” he wrote.

Matt Fuller, the politics editor for The Daily Beast, tweeted in response: “I can tell you we stand behind every word and feel very solid about the story.”

The allegation against Walker is the latest in a series of stories about the former football star’s past that have rocked the first-time candidate’s campaign in one of the most competitive Senate races in the country. Earlier this year, Walker acknowledged reports that he had three children that he had not previously talked about publicly.

As a Senate hopeful, Walker has supported a national ban on abortions with no exceptions for cases involving rape, incest or a woman’s health being at risk.

“I’m for life,” Walker has said repeatedly as he campaigns. When asked about whether he’d allow for any exceptions, he has said there are “no excuses” for the procedure.

Walker has sidestepped many questions about his earlier support for a national abortion ban, instead trying to turn the issue against his Democratic rival, Senator Raphael Warnock, who supports abortion rights. Walker often characterises abortion as “a woman killing her baby” and says he doesn’t understand how Warnock, a Baptist pastor, can support the procedure being legal.

Senator Warnock was dismissive when told of The Daily Beast story and when asked whether it might affect the outcome in Georgia. “I’ll let the pundits decide,” he said.

On Monday night, Walker appeared on Fox News where he was asked if he recalled sending a $700 check to a girlfriend.

“Well, I sent money to a lot of people,” he said. “I give money to people all the time because I’m always helping people. I believe in being generous. God has blessed me. I want to bless others.”