Berlin said last year it would deploy roughly 4,800 troops in Lithuania at a permanent base on NATO's eastern flank as tensions rise with Russia.

The advance party is tasked with "planning the brigade's transfer to Lithuania and coordinating military infrastructure needs," the Lithuanian Defence Ministry stated.

"Lithuania's security is our security," German ambassador Cornelius Zimmermann told reporters as the fist troops landed.

Berlin has committed to deploying a heavy brigade including tank units to Lithuania by the end of 2027 though the two NATO members have yet to agree on who will pay for housing of the troops and other costs.

An agreement is expected, however, by the end of the year.

Lithuanian Defence Minister Laurynas Kasciunas says his country plans to spend about 800 million euros ($870 million) on the brigade in coming years.

Germany heads up and provides around half of a 1,500-strong NATO enhanced tactical group which was stationed in Lithuania in 2017 and which will ultimately form part of the new brigade.