“This incident demonstrates Russia’s disrespect of international norms and for the sovereign airspace of an Allied nation. We remain vigilant, ready and prepared to secure NATO airspace 24/7,” said General Jeff Harrigian, Commander of NATO’s Allied Air Command.
Danish Quick Reaction Alert aircraft were launched to counter the violation, however the violating Russian fighter turned back before interception. The Danish jets remained airborne and patrolling to protect the sovereignty of Danish airspace.

A United States Air Force B-52 bomber taking off from Fairford, to participate in training activity "Allied Sky".
Photo courtesy of United States Air Force
The unauthorised intrusion of sovereign airspace is a significant violation of international law. Friday’s incident is the first of this kind for several years and indicates a new level of Russian provocative behavior.
The B52 bomber was taking part in the long-planned training activity “Allied Sky”, where six B52 aircraft flew over all 30 NATO member nations in one single day, accompanied by and training with around 80 fighter aircraft from across the Alliance.

A Russian Su-27 fighter aircraft intercepting the United States Air Force B-52 bomber. Another Russian fighter jet followed the US aircraft well into Danish airspace.
Still image taken from a video courtesy of United States Air Force.