Russia on Thursday "categorically" rejected a German court's ruling that it ordered the 2019 assassination of a former Chechen commander in a Berlin park.
The verdict resulted in Germany expelling two Russian diplomats and triggered a wave of protest from Russian officials.
But President Vladimir Putin's spokesman on Thursday expressed hope that the spat would not affect the Kremlin's ties with the new German leader Olaf Scholz.
A Berlin court on Wednesday sentenced Russian suspect Vadim Krasikov, alias Vadim Sokolov, to life in jail after finding him guilty of gunning down 40-year-old Georgian national Tornike Kavtarashvili.
The judge in the case said Russian authorities had ordered Krasikov to assassinate the victim as retaliation for being a Kremlin opponent.
"We categorically disagree with this conclusion," Kremlin spokesman Dmitry Peskov told reporters.
"We believe that this should in no way affect the prospects for establishing a dialogue between President Putin and the new Chancellor of Germany."
The incident threatens to strain Russia's relations with Germany's new government, which has vowed a tougher stance towards Moscow.
Earlier on Thursday, Russia's foreign ministry said Moscow was "deeply disappointed" with Germany's decision to expel two Russian diplomats and vowed to retaliate.
"In Berlin, there should be no doubt that the Russian side will take retaliatory measures," the ministry said in a statement without providing further details.
Germany had already thrown out two Russian diplomats shortly after the murder in protest at Moscow's perceived lack of cooperation with the probe.
Russia denied any connection to the killing and responded with a tit-for-tat move.