British politician Boris Johnson said in a BBC documentary that Russian President Vladimir Putin threatened him with a missile strike during an "extraordinary" phone call before Russia's invasion of Ukraine last year.

Johnson, U.K. prime minister at the time, said Putin told him it "would only take a minute," the BBC reported Monday.

Putin's threat came after Johnson warned that the war would be an "utter catastrophe," the BBC reported.

Johnson discussed the exchange for a documentary on Putin's interactions with world leaders over the years, the BBC said.

A Kremlin spokesman called the assertion a "lie," the BBC reported.

According to the BBC, Johnson warned Putin that invading Ukraine would lead to Western sanctions and more NATO troops on Russia's borders. And he also told him Ukraine wouldn't join NATO "for the foreseeable future."

"He threatened me at one point, and he said, 'Boris, I don't want to hurt you but, with a missile, it would only take a minute' or something like that. Jolly," Johnson said in the documentary.

"But I think from the very relaxed tone that he was taking, the sort of air of detachment that he seemed to have, he was just playing along with my attempts to get him to negotiate."

Putin had been "very familiar" during the "most extraordinary call," Johnson said in the documentary.

The BBC noted there was no reference to the exchange in accounts released to the media of the call between Johnson and Putin. With all officially arranged phone calls, there are always detailed minutes taken by an official in the prime minister's office on Downing Street — retained for the archive.

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