Bulgaria stands to lose the servicing agreement for all of its MiG-29 multirole fighter jets after making a servicing contract with Poland, which does not have a license to carry out the repairs.

Bulgaria's plan to have Poland rather than Russia provide maintenance for its MiG-29 fighters endangers the future of the country's air force, according to retired air force head General Miho Mihov.

Poland and Bulgaria signed a deal to renovate the planes in August, without the consultation of all members of its Defense Council, the consultative body of its Ministry of Defense. Mihov noted that because Poland does not have a license to service Bulgarian MiG-29 fighters, the repairs will void the agreement between Russia and Bulgaria on obligatory servicing of the planes.

"We informed the defense minister that Poland does not have a license to carry out repairs on the Bulgarian MiG-29s. The case has not been discussed at the Defense Council with the participation of all of its members," Mihov said in comments carried by Polish media.

Bulgaria, a NATO member, recently had tensions with the Russian government over cancellations of the South Stream pipeline and more recently, not allowing Russian aid planes to Syria to fly across its airspace.

Russia's Foreign Ministry commented saying that it questions just how independent Bulgaria's decision to close the airspace really was.

Russia's MiG Aircraft Corporation has sent letters to Bulgaria's government warning that the servicing agreement would be voided, the latest of which was published in Bulgaria's Standard newspaper.

Bulgaria has a total of 16 MiG-29 fighter jets, of which four are operational according to Poland's TVN24 television. Other than the Russian-made MiG-29 aircraft, Bulgaria also has three aging, Soviet-made MiG-21s.