Putin announced on Sunday that Russia had successfully tested the Burevestnik nuclear cruise missile and would work on its deployment.

The Russian military claims that the missile was in the air for about 15 hours and flew about 14,000 kilometers.

"They know we have a nuclear submarine, the most powerful submarine in the world, right off their shores," Trump told reporters.

"I mean, it doesn't have to fly 8,000 miles," he added.

"And by the way, I don't think Putin should talk like that," Trump continued.

"He should have ended the war. A war that was supposed to last a week is now in its fourth year, and that's what he should be doing, not testing missiles."