Amari: American troops landed in Estonia on Monday, rounding out the 600-man force sent by Washington to Poland and the Baltic states to allay concerns over the escalating Ukraine crisis.
"The transatlantic link is not something that Estonians take for granted. Rather, we see it as a vital element of security in an unsecure world," Estonian President Toomas Hendrik Ilves said at the welcome ceremony.
"This is why we so appreciate Allied boots on the ground here."
Around 150 troops from the 173rd Airborne Brigade landed at the Amari air base in western Estonia. They will be stationed at the Baltic seaport of Paldiski.
Another 450 soldiers already arrived in Latvia, Lithuania and Poland over the last week after the United States said it had decided to increase its presence in the region to reassure its NATO allies and partners.
"The only military danger in the Baltic Sea region is Russia. Russia does not recognise neutrality: you are either with them or against them," Estonian army chief Riho Terras said at the weekend.
"That being the case, the presence of western armed forces in our region is of vital importance," he said, calling on soldiers from other NATO member states to follow suit.
NATO has also stepped up air patrols over the Baltic states, which spent five decades under Soviet occupation until 1991 and joined the western military alliance in 2004.