Germany “firmly rejects” Russia’s threat of “serious” consequences for the transit stop, government spokesman Steffen Hebestreit said at a regular press conference.
Germany called on Russia “not to take any measures that violate international law”, Hebestreit said.
Moscow has demanded that Lithuania immediately lift the restrictions, which the Baltic nation says were taken in compliance with European sanctions over Ukraine.
The threatened retaliation would have a “serious negative impact on the population of Lithuania”, Russia’s security council chief Nikolai Patrushev said on Tuesday.
The situation in Lithuania was such that Germany and its Nato partners were offering “massive support” in the form of “soldiers, weapons” and “equipment”, German defence minister Christine Lambrecht said later on Wednesday.
“We will not give a millimetre” of Nato territory, Lambrecht said.
“That is the strength that we have shown in recent weeks and which (Russian President Vladimir) Putin probably did not expect,” she said.
Germany has pledged to deploy more troops to Lithuania to strengthen Nato’s eastern flank, which borders Russia.