A Russian newspaper has reported that the military has begun deploying S-400 mobile surface-to-air missiles in Kaliningrad, the Baltic exclave bordered by Poland and Lithuania.
Izvestia cited unnamed military officials as saying the missiles arrived Friday, but did not say how many. The Defense Ministry declined comment on the report.
S-400s, Russia's most advanced surface-to-air missiles, have a range of 120-400 kilometers (75-250 miles).
The report comes amid rising tension between the U.S. and Russia over Washington's plans for a missile-shield system in Europe, which Russia contends threatens its own defenses.
S-400s are already deployed around Moscow and are planned to be placed in the Pacific Far East this year.