Russian President Vladimir Putin said a Georgian man murdered in Berlin in August was himself a killer who took part in bloody acts on Russian soil and that Moscow's requests for his extradition had not been heeded.
Asked at a news conference in Paris if Russia would respond in kind to Germany's expulsion of two Russian diplomats over the man's killing, Putin said: "There are unwritten laws in such cases: you expelled our diplomats, we expel yours."
German prosecutors suspect Russian or Chechen involvement in the murder of the man in a Berlin park in August. Russia has denied any involvement and said last week it would retaliate for what it called Germany's "unfriendly" move.
Germany said last Wednesday it had expelled the two Russian embassy employees in protest over what it said was Moscow's lack of cooperation in the investigation into the murder.
The expulsions marked an escalation in already heightened tensions between Russia and Germany and other Western countries following the poisoning last year of a former Russian spy, Sergei Skripal, and his daughter on British soil.
Chancellor Angela Merkel told Monday's joint news conference with Putin, and the leaders of France and Ukraine, that she had told the Russian president in a bilateral meeting that Berlin expected Moscow to provide information for the investigation.
But Putin told the same news conference in Paris that the man had fought on the side of anti-Moscow separatists in Russia's mainly Muslim north Caucasus region.
"He is a cruel and blood-thirsty person. In just one of the attacks in which he took part, he killed 98 people. He was one of the organizers of explosions in the Moscow metro," Putin said, without offering evidence of his involvement.
On the killing in the Berlin park, Putin said: "I don't know what happened to him. It's a criminal milieu and there, anything can happen."
"But I believe that it is not appropriate to expel diplomats who have nothing to do with this, purely on the basis of preliminary conclusions," Putin said.
The Russian-Georgian victim, known as Zelimkhan Khangoshvili, was shot dead in August as he was heading to a mosque.
Surveillance camera footage showed the suspect had cycled up close to the victim who managed to push him over. The victim then tried to flee but the killer pursued him and shot him at least twice, German prosecutors have said.
There were sufficient leads to indicate the Russian state or Chechen authorities ordered the killing, they said, adding that Moscow had designated the victim, who had fought against Russians in Chechnya, a terrorist.
A suspect was detained soon after the killing and investigators had discovered his real identity. They named him only as Vadim K. or Vadim S. Der Spiegel magazine has reported his passport number links him to Russian security services.