Russia declared eight Greek diplomats unwelcome and gave them eight days to leave the country, the Russian foreign ministry said on Monday.
Greece in April asked 12 Russian diplomats to leave the country as a reaction to the war in Ukraine and send defense supplies to Kyiv.
The Russian foreign ministry said it had summoned the Greek ambassador to protest over what it called "the confrontational course of the Greek authorities towards Russia, including the supply of weapons and military equipment to the Kyiv regime."
The ministry said it had also protested against a Greek decision to declare a group of Russian diplomats "personae non gratae."
The Greek Foreign Ministry said on Monday it regrets Moscow's decision. "There is no basis for the decision of the Russian authorities to expel members of the staff of the Greek diplomatic and consular authority in Russia," it said in a news release.
Greece is a member of NATO and the European Union and has joined EU sanctions against Russia over its actions in Ukraine.