Kremlin spokesman Dmitry Peskov told reporters what Johnson had said was not true, or "more precisely, a lie."

Peskov said Putin had explained to Johnson how, if Ukraine joined the Western NATO alliance, U.S. or NATO missiles placed near Russia's borders would mean any missile could reach Moscow in a matter of minutes, and suggested that there may have been a misunderstanding.

"If that's how this passage was understood, then it's a very awkward situation," Peskov said.