SOFIA, March 21 (Xinhua) -- Russia would provide integrated logistics support for Bulgaria's MiG-29 jet fighters based on a framework agreement signed here on Wednesday, Bulgarian Ministry of Defense said in a statement.

Under the agreement worth 81 million BGN (50.8 million U.S. dollars), the Russian Aircraft Corporation MiG would provide spare parts and services for Bulgaria's 15 MiG-29s for a period of four years, the statement said.

The spare parts would be replaced by Bulgarian engineers at the country's Graf Ignatievo Air Base, the statement said.

Bulgaria has been a NATO member since 2004, but the 15 MiG-29 fighters still make up the backbone of its current air defense.