The US and Bulgarian air forces have teamed up to conduct joint air policing of Bulgarian airspace, according to Nato.

Expected to begin this September, the joint air policing mission forms part of Nato's improved air policing measures for eastern allies.

Nato has launched the new measures for the first time, in response to a request by the Bulgarian authorities.

Conducted by national means until now, air policing ensures the safety of the airspace and its users.

Two US Air Force F-15 fighter jets will patrol the Bulgarian airspace for a week, alongside MIG-29 twin-engine jet fighter aircraft from the Bulgarian Air Force.

Nato Deputy Secretary General Alexander Vershbow said: “Nato takes its responsibility to ensure the safety and integrity of our airspace very seriously.

"This mission is a demonstration of solidarity and support for our Ally Bulgaria.”

According to Nato, air policing scrambles respond to military and civilian aircraft that do not follow international flight regulations, or approach Nato airspace without proper clearance.

"Nato takes its responsibility to ensure the safety and integrity of our airspace very seriously."

Additionally, such aircraft fail to properly identify themselves, communicate with Air Traffic Control, or file flight plans.

Nato said that air policing helps ensure equal protection for all allies, including those who do not have the full range of air defence assets in their own militaries.

Earlier this month, Nato air policing jets have trained with US bombers over the Baltic Sea.

Image: US Air Force F-15 fighter jets will patrol the Bulgarian airspace, alongside Bulgaria's MIG-29s. Photo: courtesy of Nato.