Moscow threatens NATO member Lithuania over transit ban on goods to Russia's European exclave Kaliningrad

Lithuania's decision to ban the transit of certain goods between Russia and its isolated exclave of Kaliningrad has provoked wrath among top officials in Moscow, and even a threat of retaliation against the European nation. Kaliningrad shares land borders with two NATO nations, Lithuania and Poland, but not Russia. Captured from Nazi Germany by the Soviet Red Army in 1945 and later ceded to the Soviet Union, the Russian territory is home to about 500,000 people.

While it is surrounded on two sides by NATO nations, it's a strategically vital patch of ground for Moscow as it provides Russia's only Baltic Sea coastline. It is home to the Russian military's Baltic Fleet, and a number of advanced nuclear-capable Iskander missile installations.

But the isolated patch of ground relies on its rail connection to the rest of Russia for the majority of its civilian imports. That rail line runs through Lithuania and then neighboring Belarus, which is a Russian ally.