The Russian Defense Ministry has downplayed claims that its military aircraft have been involved in "provocations" in Bulgaria's airspace over the past month.

On Sunday, Bulgaria's Defense Minister Nikolay Nenchev argued that as many as ten violations of the country's airspace had been committed in a month.

In his words, areas where Russian aircraft have flown are part of Bulgaria's "area of responsibility" as part of NATO.

"First and foremost, clarifications have to be sought, and not from us [but] from Mr Minister [Nenchev], as to how far from Bulgaria's air border their imaginary area of responsibility for NATO airspace is extended," RBC daily quotes Igor Konashenkov, the head of the Russian Defense Ministry's press office, as saying.

In his words, Russia's Defense Ministry "cannot hide its astonishment" at the claim of Nenchev.

While Russia does conduct flights over the Black Sea, these are regularly scheduled and carried out fully in line with international rules that apply in neutral waters, Konashenkov has said.

Transponders are always switched on, he has added, contrary to Nenchev's words that Russian fighter jets would turn off the equipment in question (which allows easier location of the aircraft) while flying over the Black Sea.

"Before announcing in front of TV cameras the adopted "preventing measures" by the Bulgarian military, we would recommend Mr Minister to check the reports of his subordinates on the real state of affairs," the Russian official has made clear, arguing Bulgarian authorities have not officially turned to Moscow to make their case.