Lithuania's President Gitanas Nauseda arrives for an European Union Summit with all 27 EU leaders at the European Council building in Brussels, Belgium December 16, 2021. Kenzo Tribouillard/Pool via REUTERS
Lithuania's President Gitanas Nauseda arrives for an European Union Summit with all 27 EU leaders at the European Council building in Brussels, Belgium December 16, 2021. Kenzo Tribouillard/Pool via REUTERS Reuters / POOL

Lithuania's president called on Saturday for Baltic states' security to be boosted with U.S. troops as the region worries about Russia's massing of troops near Ukraine in what Western nations view as a threat of invasion.

"The Russian military buildup at the eastern NATO border is changing the security situation," President Gitanas Nauseda said in a statement after the meeting U.S. Defense Secretary Lloyd Austin in Vilnius.

"It is critically important to strengthen the (Baltic states) regional security with additional troops from the United States and quicken cooperation in military procurement," he added.

Since 2019 the United States has deployed rotating groups of about 500 troops and equipment in Lithuania, and in his statement Nauseda called on Washington to make this a permament deployment.

Nauseda said earlier that Lithuania fears that Europe is "on the brink of war".

U.S. President Joe Biden said on Friday he was convinced that President Vladimir Putin has made the decision to invade Ukraine. Moscow has denied it plans to invade its neighbour.

Austin piled praise on Lithuania for standing up to pressure from Russia, whose military buildup has included sending tens of thousands of troops to Belarus - neighbouring Lithuania - for joint exercises that are due to end on Sunday.

Lithuanian Prime Minister Ingrida Simonyte said her country believes the Russian troops in Belarus may stay there for an extended period.

"We can say with large certainty that we will not see the (Russian) troops withdrawn quickly, if at all," she told reporters.

Belarus' President Alexander Lukashenko met Putin on Friday, saying beforehand the soldiers could stay as long as needed.

Simonyte said that if Russian troops stay, this could put pressure on the Baltics' only overland connection to the rest of the European Union, a narrow strip of land between Belarus and Russia's Kaliningrad enclave known as the Suwalki corridor.

"This would be a major change to the security situation. We will need to adjust accordingly so that the Suwalki corridor and the Baltic states are defended," she said.

Austin also noted pressure on Vilnius from China, which is curbing trade with the Baltic state to punish it for recognizing self-ruled Taiwan.

"I know that I'm visiting at a time when Lithuania is under tremendous pressure from all sides," Austin told Nauseda.