Russia was behind the daytime killing of a Georgian man in a Berlin park, German prosecutors said on Thursday.
The allegation was made as a Russian man was charged with the murder.
The victim, a Georgian national of Chechen ethnicity identified as "Tornike K", had fled to Germany in 2016 after fighting Russian troops in Chechnya.
He was reported to have already survived multiple assassination attempts there, and to have received continuous threats while in Germany.
Prosecutors said in a statement the suspect was tasked to "liquidate" the victim by "state agencies of the central government of the Russian federation" some time before mid-July last year.
The suspect "accepted the state killing assignment", prosecutors said. "He either hoped for a financial reward or he shared the motives of those who tasked him to kill a political opponent and take revenge for his participation in earlier conflicts with Russia."
The Russian ambassador to Germany, Serguei Netschajew, denied the accusations on Thursday.
"We consider these accusations as unjustified and unfounded," Netschajew said.
Tornike K. was cycling in Berlin's Kleiner Tiergarten park in August last year when he was attacked from behind by the suspect and shot three times, the prosecutors' statement added.
The suspect was arrested in the area shortly after the attack and has remained in custody since.
This case, combined with alleged Russian involvement in the hacking of the German parliament in 2015, have weighed on diplomatic relations between the two nations.
Germany announced last month that it would seek European Union sanctions against a Russian suspect in the hacking case.
"We once again invited the Russian ambassador for a meeting at the foreign ministry today to make our position unmistakably clear again to the Russian side, and the German government expressly reserves the right to take further measures in this case," German Foreign Minister Heiko Maas said on Thursday after the prosecutor's announcement.
In December, the German authorities, regretting a lack of cooperation from their Russian counterparts in the investigation, decided to expel two Russian diplomats.