MSNBC host Joe Scarborough reported on the air Wednesday morning that when Donald Trump met for a briefing with an unnamed foreign policy expert, the GOP nominee allegedly asked, “Why can’t we use nuclear weapons?” several times.

Scarborough made the claim during an interview with retired Air Force Gen. Michael Hayden, who expressed concern about how Trump would be an “erratic” and “inconsistent” commander-in-chief.

When Hayden curtly said he’s not aware a single one of his colleagues advising Trump on foreign policy, Scarborough spoke up.

“I have to follow up with that, but I’ll be very careful here. Several months ago, a foreign policy expert on the international level went to advise Donald Trump, and three times he asked about the use of nuclear weapons. Three times he asked, at one point, ‘If we have them, why can’t we use them?” Scarborough said.

“Trump asked three times?” commentator Mike Barnicle asked.

“Three times in an hour briefing, ‘Why can’t we use nuclear weapons?’” Scarborough said again.

Several beats of stunned silence went by before co-host Mika Brzezinski said, “Be careful, America and be careful, Republican leaders. Your party is blowing up.”

Scarborough turned the conversation back to Hayden, asking the retired general about the timeline and steps if a President chooses to use nuclear weapons. Hayden responded the system in place is “designed for speed and decisiveness. It’s not designed to debate the decision.”

The “Morning Joe” host, a former GOP congressman, did not name the “foreign policy expert” he said met with Trump. Scarborough also did not say how he knew about the briefing or Trump’s remarks.

In an interview with Fox News later on Wednesday, Manafort said it was “absolutely not true” that security briefing meetings have been held.

“The idea that he’s looking at trying to understand where to use nuclear weapons, it just didn’t happen,” he said. “I was in the meeting. It didn’t happen.”

Trump has said he would “never, ever” rule out using nuclear weapons to fight the Islamic State as President. In a March interview, after MSNBC’s Chris Matthews said nobody wants to hear a candidate for President talking about the use of nuclear weapons, Trump fired back: “Then why are we making them?”

Watch the exchange via MSNBC:

Watch: What are some major concerns about Trump’s handling of national security? Hayden and #morningjoe weigh in. https://t.co/FyFoSmJlJI — Morning Joe (@Morning_Joe) August 3, 2016

This post has been updated.