Kaliningrad

Lithuania - a member of the Nato military alliance - also shares a border with Kaliningrad, a heavily militarised Russian exclave on the Black Sea.

A pair of RAF Typhoons were scrambled to intercept a Russian Ilyushin Il-20M "Coot-A" intelligence aircraft over the Baltic Sea on 15 April, while another two Typhoons intercepted an unknown aircraft leaving the Kaliningrad airspace on 17 April.

Sweden has now joined Nato, meaning that eight Nato countries now border the Baltic Sea where Russia maintains two strategic footholds, in St Petersburg and Kaliningrad.

Estonia and Latvia share land borders with Russia, while Lithuania is adjacent to the Russian enclave Kaliningrad, which also shares a border with Poland, and Moscow's close ally, Belarus.

International Atomic Energy Agency Director-General Rafael Grossi said he gained an understanding of Russia’s position during a meeting last week in Kaliningrad with Alexey Likhachev, the director-general of the Russian nuclear energy agency Rosatom.