Moscow warned on Tuesday that Lithuania would face “serious” consequences for banning the transit of EU-approved goods through its territory to the Russian enclave of Kaliningrad. The Kremlin called the decision “unprecedented” and “hostile”, calling on the top EU diplomat in Moscow to oppose it. The Kaliningrad region, hundreds of miles west of the rest of Russia, has become the last flashpoint between Moscow and Europe as the effects of the Kremlin war on Ukraine widen. The town and port of Kaliningrad is located on the south coast of the Baltic Sea between Lithuania and Poland, which are both part of the European Union and NATO. The region, home to the Russian Baltic Fleet, receives much of its supplies through Lithuania and Belarus and has sea links with Russia. How Kaliningrad, Russian territory surrounded by NATO, gets involved in the war in Ukraine Lithuania’s state railway company LTG announced on Friday that it would no longer allow Russian goods subject to EU sanctions, including coal, metals and construction materials, to pass through the country to Kaliningrad – something the regional governor said that it will affect almost half of its imports. Officials in Moscow have promised retaliation. “Russia will definitely react to such hostile actions,” Nikolai Patrushev, secretary of the Russian Security Council, said during a visit to Kaliningrad on Tuesday, according to Russian news agencies. He promised “appropriate measures” in the near future, but did not give details. “Their consequences will have a serious negative impact on the Lithuanian population,” Patrushev said. Russian Foreign Ministry spokeswoman Maria Zakharova described Lithuania’s decision as “unacceptable”, according to the Russian news agency Tass. “The consequences will follow,” he said. Lithuania, one of Ukraine’s most ardent Baltic states, has said it is applying sanctions from the European Union – part of a campaign by Western governments to pressure Russian President Vladimir Putin to invade Ukraine. Russia’s move to Belarus poses risks to more than Ukraine The Lithuanian railway company told the Washington Post that the movement of passengers and cargo that are not subject to EU sanctions will continue. EU foreign policy chief Josep Borrell has dismissed Russian allegations that Lithuania’s move was an exclusion. Land transit between Kaliningrad and other parts of Russia “has not been stopped or banned,” he told a news conference Monday. “Lithuania has not taken unilateral national restrictions and only applies the sanctions of the European Union.” Goods such as fuel and cement could still be transported from Russia by sea, Kaliningrad Governor Anton Alikhanov said. Exclave operates as a special economic zone with low taxes, although Western sanctions have hit its economy. On Monday, Alikhanov said that while shops and gas stations were stocked, people rushed to the building stores because construction materials could no longer be reached by rail. Amar Nadhir, Amy Cheng and Annabelle Chapman contributed to this report.