A military transport plane carrying German soldiers arrived in Kaunas -- the Baltic state's second largest city -- to begin the deployment, an AFP photographer saw.

Germany already has around 550 soldiers stationed in Lithuania and leads the NATO multinational battalion there.

The additional forces will be backed up by 100 military vehicles, the commander of the battle group Daniel Andrae told reporters.

"We are looking forward to integrate them into the battle group," he said.

"For me as a commander it is always good to get additional capabilities and forces... to be ready for everything which might come up," he added.

The Baltic nation borders both Russia and Belarus.

NATO's "enhanced forward presence" in Poland and the Baltic states, all of which are alliance members, was decided following Russia's annexation of Crimea in 2014.

"Germany's decision to send more troops to Lithuania is an important and timely decision, demonstrating NATO's solidarity, unity and commitment to collective defence," Lithuanian Defence Minister Arvydas Anusauskas said in a statement.

The boosted German force makes Lithuania Germany's second-biggest deployment after Mali.

With more than 100,000 Russian troops massed on the Ukrainian border, fears are mounting that a major conflict could break out in Europe.

As part of the intensive diplomacy sparked by security tensions, German Chancellor Olaf Scholz landed in Kyiv on Monday for crisis talks ahead of a visit to Moscow.