President Trump is sticking with his argument that millions of illegal immigrants voted in the 2016 presidential election, amid calls for him to provide proof and questions about whether he’ll indeed have an official probe into the issue.

“Many people have come out and said I am right,” Trump said in an interview with Fox News’ Bill O’Reilly to be aired Sunday before the NFL Super Bowl.

Watch the O'Reilly Super Bowl LI interview with Trump at 4 pm ET Sunday on Fox Sports. Tune in for more of the interview on "The O'Reilly Factor" Monday and Tuesday at 8 pm ET on Fox News Channel.

Trump didn’t directly answer a question about whether he, in fact, has evidence -- but suggested that he has seen voter-registration records that suggest widespread voter fraud.

“We can be babies, but you take a look at the registration,” Trump said. “You have illegals, you have dead people, you have this. It’s really a bad situation.”

Trump became president by winning the Electoral College vote but did not win the popular vote. And losing that vote to Democratic nominee Hillary Clinton by an estimated 3 million ballots has been a continuing source of contention with him.

Last month, Trump suggested he would ask for a “major investigation” through the Justice Department. And he purportedly was considering signing an executive order to start the process. But the administration has not taken any public action on the issue in roughly the past 10 days.

Also on Sunday, Senate Majority Leader Mitch McConnell, R- Ky., told CNN’s “State of the Union” that he doesn’t want to spend federal money to investigate Trump’s allegation.

Trump also said in the Fox interview that he has "respect" for Russian President Vladimir Putin, but that respect does not mean they'll get along.

"I say it’s better to get along with Russia than not,” he said. “And if Russia helps us in the fight against ISIS, which is a major fight, and Islamic terrorism all over the world -- that’s a good thing. … Will I get along with him? I have no idea."

Pressed about Putin's history of violence, Trump said: "There are a lot of killers. We’ve got a lot of killers. What do you think? Our country’s so innocent?