Russia has warned Lithuania of "serious" consequences over a move by the Baltic state to block the rail transfer of some goods through its territory to the Russian exclave of Kaliningrad.
Russian Security Council secretary Nikolai Patrushev, a close aide to President Vladimir Putin, said at a meeting in the exclave on Tuesday that the blockade by Lithuania is against the principles of international law.
Patrushev said Russia will surely respond to such hostile actions. He said appropriate measures will be taken shortly and they will have serious negative consequences for Lithuanian citizens.
Patrushev stressed the need to beef up border security in the country's northwest, saying the move by Finland and Sweden to apply for NATO membership is posing a fresh threat to Russia.
Kaliningrad is a key strategic hub where the Russian Navy's Baltic Fleet is headquartered.