El Paso’s Republican mayor, Dee Margo, said that President Trump mocked him as a “RINO” (Republican in Name Only) in a private conversation during Trump’s visit to the Texas city last week after its deadly mass shooting.

In an interview with PBS’s Frontline on Wednesday, Margo said that Trump made the RINO remark, which Republicans hurl at one another to imply they’re not conservative enough, after the mayor previously pushed back against the president’s false claim that a border fence had made El Paso safer.

“He said, ‘You’re a RINO,’ and I said, ‘No, sir. I am not a RINO,’” Margo told Frontline. “I said … ‘I simply corrected the misinformation you were given by [the Texas] attorney general, and that’s all I did.’”

In response, Trump “just kinda grinned,” Margo said.

The conversation took place when Margo accompanied Trump in a car back to the airport after the president’s controversial visit to meet survivors of the shooting.

During their conversation, Margo said that when he told the president about the history of El Paso and that it was not a crime-ridden city, it “seemed to resonate” with Trump.