NATO member Estonia's airspace was violated by three Russian military jets on Friday, its government said, amid an increasingly tense atmosphere on the alliance's eastern flank.

Estonia said on Friday local time three MiG-31 fighter jets entered its airspace without permission and stayed there for a total of 12 minutes.

NATO responded immediately and intercepted the Russian jets which violated Estonian airspace, a NATO spokesperson said.

Estonia's Foreign Minister Margus Tsahkna, said: "Russia has violated Estonian airspace four times already this year, which is unacceptable in itself, but today's violation, during which three fighter jets entered our airspace, is unprecedentedly brazen.

" Russia's ever-increasing testing of borders and aggressiveness must be responded to by rapidly s

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