Moscow, June 28 : In a retaliatory move, Russia has declared eight Greek diplomats "personae non gratae", ordering them to leave the country within eight days, the Foreign Ministry said in a statement. Greek Ambassador to Moscow Ekaterini Nassika was summoned to the Foreign Ministry in protest over the expulsion of Russian diplomats in Athens and Greece's supply of weapons and military equipment to Ukraine, Xinhua news agency quoted the statement issued on Monday as saying. The measures were taken as a direct response to the hostile actions of the Greek authorities, and Moscow will reserve the right to respond if Athens continues to take such an anti-Russian course, it added. Greece however, expressed "deep regret" over Russia's move. "We express our deep regret for the decision of the Russian authorities to declare eight members of the Greek Embassy in Moscow, as well as the Consulate General in Moscow, as personae non grata," said a Greek Foreign Ministry statement. "There is no basis for the decision of the Russian authorities to expel members of the staff of the Greek diplomatic and consular authorities in Russia," it added. The Greek Embassy in Moscow and consular authorities in Russia "will continue to make every effort with all means at their disposal in order to continue to carry out their mission under particularly adverse conditions", the Ministry added. /IANS