Russia's Defense Ministry said earlier on Thursday that it had scrambled fighter jets to intercept a US B-52 strategic bomber after it began flying toward Russia's borders, Reuters reported.

"In general, I will limit myself to only saying that of course such actions by the United States do not lead to a strengthening of an atmosphere of security and stability in the region that directly adjoins Russia's borders," Kremlin spokesman Dmitry Peskov told reporters on a conference call.

"On the contrary, they create additional tensions."

Russia's European exclave of Kaliningrad is on the Baltic Sea.