Any U.S. move to place new missiles in Europe would cut the time it took some U.S. missiles to reach Moscow to 10-12 minutes, Putin said, something he called a serious threat.
Such a scenario, if left unmatched, would open up the possibility of Russia being hit by a nuclear strike before its own missiles fired in response could reach U.S. territory.
The Russian land-based missiles that currently target the United States are based on Russian territory and therefore the flight time to major U.S. population centers would be longer than for U.S. missiles deployed in Europe.
Source: Moscow ready to cut time for nuclear strike on U.S. if necessary: Putin | Reuters