Russia said Monday it was expelling three diplomats from the Slovak embassy in Moscow in a tit-for-tat move after Bratislava forced out three Russians amid a growing diplomatic spat with Europe.

"The Russian side, guided by the principle of reciprocity, decided to expel ... three diplomatic staff of the Slovak Embassy in Moscow," the Russian foreign ministry said in a statement.

Slovakia announced on Aug. 10 that it was removing three Russian embassy staff over what it said was a "serious crime," with local media citing a possible link with the killing of a former Chechen rebel in a Berlin park last year.

German prosecutors accused Russia of ordering the killing of Zelimkhan Khangoshvili, a 40-year-old Georgian national who was shot twice in the head at close range last year.

Russia's foreign ministry described Bratislava's decision to remove its diplomatic staff as an "unfriendly step" that contradicted the "traditional spirit" of shared ties.

This is the third expulsion of European diplomats by Russia in a week.

A Norwegian diplomat was forced to leave Russia Friday in response to Norway's removal of a Russian diplomat over activities "not compatible with his status."

An Austrian diplomat on Aug. 24 was expelled from Russia in another tit-for-tat move following espionage allegations from Vienna.

In June, Russia sent home two Czech diplomats, retaliating over the expulsion of two of its own embassy workers from Prague for spreading rumors of a poisoning plot.