The warning was issued by Gennady Gatilov, Moscow's permanent representative to the UN, on the state TV channel Russia-24, Newsweek reported on Monday.
He said Moscow was monitoring Washington's plans to deploy its nuclear weapons in Britain.
"We are talking, perhaps, about the reactivation of an air base with American nuclear weapons in Great Britain," Gatilov said.
"There is also talk about the possibility of sending nuclear weapons to the Baltic states, to Poland. All this creates a tense situation. We are monitoring how developments are going in this direction. Of course, if this is so, Russia will be forced to react to this accordingly."
MP/PR