MOSCOW, September 18 (RIA Novosti) - Russia will finish upgrading MiG-29 fighters in service with the Indian air force in 2013, a Russian defense industry source has said.

Russia's MiG company signed last year a contract with the Indian Defense Ministry to upgrade over 60 MiG-29 fighters, in service since the 1980s.

"The implementation of the contract started last year, and it will be fulfilled in 2013," the source told RIA Novosti on Thursday.

According to the source, during the upgrade the MiG-29s will be fitted with advanced avionics, new multi-functional Zhuk-ME radars, a new weapon control system, as well as revamped engines.

The service life of the aircraft will be extended from 25 to 40 years.

The official said the first four Indian MiG-29 fighters are being modernized and flight-tested in Russia and the remaining aircraft will be overhauled in India with the aid of Russian experts.

The contract stipulates the construction of MiG consignment depots and service centers in India, along with simulators for pilot training.