WASHINGTON • The United States said on Tuesday it stood firmly behind Lithuania and North Atlantic Treaty Organisation (Nato) commitments to defend it after Russia warned its neighbour over restrictions on rail transit.

"We stand by our Nato allies and we stand by Lithuania," State Department spokesman Ned Price told reporters.

"Specifically our commitment to Nato's Article Five - the premise that an attack on one would constitute an attack on all - that commitment on the part of the United States is ironclad," he said.

Lithuania, a former Soviet republic, now both in Nato and the European Union, has been among the most outspoken nations in opposing Russia's invasion of Ukraine.

Lithuania said that it would restrict the rail transit of goods sanctioned by the EU into Kaliningrad, an isolated Russian enclave on the Baltic Sea sandwiched between Lithuania and Poland.

Russia has warned that it would "certainly respond" to the "hostile actions".

Asked about Russia's statements, Mr Price said: "We aren't going to speculate on Russian sabre-rattling or Russian bluster and don't even want to give it additional airtime."

For the nearly 6,000 residents living in Kybartai, near the border with Kaliningrad, reactions to Russia's threat were mixed.

Insurance worker Vitalijus Sidiskis, 59, said that while he believed it was difficult to predict what Russia might do, he would remain calm because of Lithuania's membership in the EU and Nato.

"Nothing bad will happen... because Lithuania is in Nato and in the European Union," he told Reuters. "I don't believe that they will be aggressively attacking us."

Other residents said the threat had overshadowed other problems, such as sky-high inflation.

"We work near the border and the shooting and the manoeuvres are a bit worrying," said Ms Galina Mateikuniene, a 52-year-old seamstress.

"We are probably more afraid of war, of an invasion. The economy is the economy."

AGENCE FRANCE-PRESSE, REUTERS