Sen. Jeff Flake, R-Ariz., says he and former President Barack Obama have kept in touch even after the Democrat left the White House.

"We talk," Flake said during a wide-ranging interview with Obama's former aide, David Axelrod on "The Axe Files," which aired Saturday evening on CNN.

"He called me after the shooting to make sure I was alright after I gave my speech," Flake continued. He didn't specify which shooting or which speech, but appeared to be referring to his speech in October of last year, weeks after a deadly mass shooting in Las Vegas, during which he announced that he would not seek re-election in 2018.

The conversation about Axelrod's former boss was prompted when he spotted a framed photograph in Flake's office that showed Flake and his family with Obama and then-first lady Michelle Obama. It appeared to be signed by both Obamas.

"The last night he was in the White House, the day before inauguration he called just to say that he enjoyed working with me," Flake said. "And I certainly said the same. He didn't have to do that. It was very nice."

In that October speech last year, Flake delivered a scathing critique of President Trump — someone with whom he has clashed several times since Trump took office.

Flake told Axelrod that the Republican Party is in a "bad place" in the era of Trump.

Flake also wouldn't rule out a potential challenge against Trump in 2020.

"I wouldn't swear it off," Flake when asked about a run.

He said he sees Trump facing off against a "challenge from the Republican Party" and said he thinks there will be an "independent challenge, particularly if the Democrats insist on putting somebody up from the far left."