Russia has announced the expulsion of two German diplomats in a tit-for-tat response to a similar move by Berlin last week.
The Foreign Ministry in Moscow said on December 12 that it had summoned German Ambassador Geza Andreas von Geyr and informed him that the two German diplomats have seven days to leave Russia.
"Guided by the principle of reciprocity and Article 9 of the Vienna Convention on Diplomatic Relations of 1961, the Russian side has decided to declare two employees of the German Embassy in Russia personae non gratae," the statement said.
Germany last week expelled two Russian diplomats after the Federal Prosecutor's Office said on December 4 that “there is sufficient factual evidence” that either Russian government agencies or Chechen regional agencies may have ordered the killing in Berlin of a 40-year-old Georgian of Chechen origin.
The German Foreign Ministry called Moscow's move "unjustifiable" in a statement and noted "with regret the Russian government's decision to declare two employees of the German embassy in Moscow personae non gratae."
"It sends the wrong signal and is unjustified," the statement added.
Zelimkhan Khangoshvili was shot twice in the head in Berlin's Kleiner Tiergarten park on August 23.
Khangoshvili had previously fought alongside separatists in Russia's Chechnya region and later sought refuge in neighboring Georgia. Years later, he moved to Germany with his family, where he had been seeking asylum.
A 49-year-old man with a Russian passport has been detained in connection with the killing.
The suspect, also implicated in the murder of a Russian businessman in 2013, has maintained his right to keep silent.
Moscow has rejected the allegations of state involvement.
The Russian Foreign Ministry has said it would have to take tit-for-tat measures in response to Germany's "unfounded and unfriendly steps."
Still, Kremlin spokesman Dmitry Peskov told TASS that the diplomats were being expelled "as a necessary, reciprocal measure," and that he hopes "this will not become some kind of negative factor for the future development and expansion of our rather constructive dialogue with the Federal Republic of Germany."