Germany expelled two Russian diplomats from the embassy in Berlin over the murder of a former Chechen insurgent in August.
Germany's Foreign Office declared two employees of the Russian Embassy in Berlin to be unwanted people or personae non-gratae on Wednesday.
The decision comes after the August 23 killing of a Chechen from Georgia in Berlin. The Georgian citizen had been shot by a cyclist in a park in Berlin. Authorities said the suspect was a Russian man.
The German foreign office said the Russian authorities "did not sufficiently participate in the investigation of the killing".
"Serious and prompt cooperation by the Russian authorities remains imperative," Germany's Foreign Office said in a statement.
The German Federal Prosecutor's Office suspects government agencies in Russia or in the Chechen Republic to have been responsible for the murder.
The Russian foreign ministry said it would respond to the expulsion of the two diplomats, Russian news agencies reported.
The murder victim had fought alongside anti-Russian separatists in Chechnya, Reuters reported.
Russia fought Chechen separatists in two wars over the past few decades.
WATCH: Alasdair Sandford explains why the case has escalated