The European Union has protested to Russia over what it called the "forced apprehension" of a Lithuanian fishing boat by Russian border guards, it said Tuesday.
The EU's relations with Russia have been strained by Moscow's annexation of Ukraine's Crimea region and its support for pro-Russian separatists in eastern Ukraine.
Russian authorities detained the boat, the J?ros Vilkas, and its crew in "high seas waters" of the Barents Sea on Sept. 18 and towed the vessel to Russian territory, an EU spokesman said.
"We are concerned by the forced apprehension of the Lithuanian fishing vessel," the spokesman said.
Lithuania, a Baltic coast state, is an EU member that was long under Moscow's control until the Soviet Union's break-up in 1991.
"The European Union calls on Russia to respect its international obligations and to immediately release the vessel," he said, adding that the EU had raised the issue with the Russian Ambassador to the bloc, Vladimir Chizhov.
The Russian Foreign Ministry published a statement on its website last week saying Russian border guards had detained the ship on Sept. 18 after it was checked and determined to have been fishing in Russia's exclusive economic waters.
The statement said that on board the ship were found 15 tons of illegally fished crabs. It said the ship tried to move into Norway's economic zone waters during checks. The ship was later forced to sail to Russia's northern port of Murmansk.
Lithuania has also protested to Russia over the fishing boat incident and demanded that the ship and its crew be set free.