US troops arrived Saturday in Lithuania, part of a US contingent of 600 sent to the region to reassure NATO allies amid the escalating Ukraine crisis.
Lithuanian President Dalia Grybauskaite hailed the arrival of American forces as a "deterrence measure" in the region where alarm has risen over Russia's actions in Ukraine.
"We know in this situation who our real friends are coming to help," Grybauskaite told reporters, after around 150 troops from the 173rd Airborne Brigade landed at the Siauliai air base.
"If any of our guests are injured, it would mean an open confrontation not with Lithuania but with the United States," she added.
The American troops will participate in a series of exercises throughout the year, according to the Lithuanian defence ministry.
Another company of soldiers arrived in Poland on Wednesday and in Latvia on Friday and a further 150 are due in Estonia on Monday.
Washington on Tuesday said it was sending the 600 troops to the region to increase its presence in the region and reassure its NATO allies and partners.
NATO has also stepped up air patrols over the Baltic states which spent five decades under Soviet occupation until 1991 and joined the North Atlantic Treaty Organisation in 2004.