Russia is planning to start the testing and development of its fourth Sukhoi T-50 stealth fighter later this year.
Russia United Aircraft Corporation president Mikhail Pogosyan confirmed the deployment on 14 June.
"We are now testing three aircraft," he said. "A fourth will be brought in this year."
The Sukhoi T-50 stealth fighter, developed under the PAK Future Aviation programme, is Russia's first new major warplane designed since the fall of the Soviet Union and has been billed as the successor to Russia's fleet of MiG-29 and Su-27 aircraft.
Since making its first flight in January 2010, three prototypes of the T-50 have undergone flight tests and Russian Air Force colonel general Alexander Zelin told RIA Novosti in May 2012 that the Russian Air Force would receive the first batch of prototypes in 2013.
Zelin had previously revealed that the number of fifth generation T-50 aircraft included in testing would reach 14 by 2015, prior to a planned entry into service in the same year.
The Russian Air Force plans to acquire 60 of the aircraft, with India also set to acquire an advanced fighter aircraft based on the T-50.
Image: The Russian Air Force hopes to acquire 60 T-50 stealth fighters. Photo: courtesy of Maxim Maksimov/russianplanes.net.