The United States will deploy F-15 fighter jets to conduct joint air policing of Bulgarian airspace next month at the request of the authorities in Sofia, NATO has announced.

Bulgaria’s Defense Minister Nikolay Nenchev said on Wednesday the government decided to conduct joint protection of the country’s airspace with the US Air Force in a week-long mission which will commence on September 9.

Nenchev told reporters that the air policing rounds will involve two US warplanes but did not elaborate what their type will be.

“Two US F-15 fighter jets will join Bulgaria’s MIG-29s for a week on this mission, which is part of NATO’s enhanced air policing measures for eastern Allies,” the Alliance said in a statement on Wednesday.

“The enhanced air policing measures for Bulgaria are being launched by NATO for the first time, in response to a request by the Bulgarian authorities,” NATO 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,” NATO Deputy Secretary General Alexander Vershbow said in the statement.

Bulgaria's Defence Ministry said in a separate statement on Wednesday that up to eight USAF aircraft, together with coprresponding crew and service personnel, will be stationed in Bulgaria in late August to implement the joint air policing mission.

Nikolay Nenchev had said in July that at least 10 violations of the country's airspace by Russian military aircraft had been recorded in a month. The Russian aircraft had allegedly been flying with their transponders -  the electronic devices that allow to identify them – turned off, Nenchev said at the time, describing the cases as ‘’provocation’’.

Nenchev also said that the areas where Russian aircraft had flown were part of NATO member Bulgaria's "area of responsibility" within the Alliance.

Moscow has dismissed Nenchev’s claims that Russian warplanes had been involved in "provocations" toward Bulgaria.