Merkel condemns Navalny arrest, demands release: spokesman
Police seized Navalny, President Vladimir Putin's most prominent opponent, at a border control post at Moscow's Sheremetyevo airport on Sunday.
Seibert said Russia had arrested the "victim" of "attempted murder with chemical weapons" and "not the perpetrator", adding that Navalny had been in Germany to receive medical treatment after the attack.
"It is absolutely unacceptable to accuse Mr Navalny of a violation of his parole over this time" he spent in Germany, Seibert said.
But when asked whether it would affect plans to continue work on the Nord Stream 2 pipeline to bring Russian gas to Germany, Seibert said the German government's position was "unchanged".