A Bulgarian investigation into alleged espionage involving Russian non-governmental organizations is not intended to influence relations with Moscow, Prime Minister Boyko Borissov said on Wednesday.

Prosecutors charged the head of a Bulgarian non-governmental organization (NGO) on Tuesday with spying for Russia as part of a scheme they said aimed to draw Bulgaria away from its Western allies and towards Moscow.

Prosecutors said Nikolai Malinov, 50, head of the National Russophile Movement, had worked for the Russian Institute for Strategic Studies, run mainly by former foreign intelligence officials, and also for another Russian NGO, the Double-Headed Eagle, since 2010.

In his first public comments following the charges against Malinov, Borissov said his country had made its choice long ago and stands with the European Union and NATO.

Bulgaria, Moscow's most loyal satellite in Soviet times, is now a member of NATO and the European Union but has close cultural and historic ties with Russia, which remains its biggest energy supplier.