SOFIA- Bulgaria's foreign ministry said on Friday it had declared 10 Russian diplomats "persona non grata" and given them 72 hours to leave the Balkan country over what it said were activities deemed incompatible with their diplomatic status.

It is the second wave of expulsions of Russian diplomats from Bulgaria this month. On March 2, Sofia expelled two Russian diplomats over allegations they had been involved in espionage.

Bulgaria, Moscow's closest ally during the Cold War but now a European Union and NATO member state that has condemned Russia's invasion of Ukraine, has expelled eight other Russian diplomats over suspected spying since October 2019.

In a statement on its website, the foreign ministry said the Prime Minister Kiril Petkov was consulted on the expulsions and the Russian ambassador to Sofia had been informed.

The Russian embassy to Bulgaria called the move a "hostile demarche" that would hurt relations between Sofia and Moscow and to which Russia would respond accordingly.

On Monday, EU and NATO member Slovakia expelled three Russian embassy staff based on information from its secret service.

(Reporting by Tsvetelia Tsolova; Editing by Hugh Lawson and Alex Richardson)