Dozens of Abrams tanks and Bradley armoured vehicles arrived by railway at the army training area in Pabrade.

Lithuania's Defence Minister Raimundas Karoblis said the deployment of some 500 US troops scheduled to stay through the winter proves that a US military presence on NATO's eastern flank "is no longer a taboo".

"First and foremost, it is a message to Lithuania and neighbouring NATO states that allies are together with us," the minister told AFP.

"And it is also a message to Russia that the US is engaged, and it is an additional deterrence element," he added.

Ben Hodges, the former commander of US Army forces in Europe, said the US deployment was a "manifestation of American commitment to continued deterrence along NATO's eastern flank", at the time when US was pulling American troops out of Syria and abandoning its Kurdish allies.

"Nobody, including the Russians, should be confused by the Americans' commitment to NATO despite what was I think a mistake of pulling out of Syria," Hodges told AFP via telephone.

Two years ago, NATO deployed a German-led multinational battalion of around 1,000 troops to Lithuania, an EU and NATO nation of 2,8 million people.

The alliance installed similar battalions in Poland and Baltic states Estonia and Latvia as tripwires against possible Russian adventurism in the region after Moscow's 2014 annexation of Crimea from Ukraine.

The entire region had been dominated by the Soviet Union for more than 40 years after World War II.