Russia could start tests of its fifth-generation fighter in late 2009 or early 2010, a deputy prime minister said on Wednesday.

"We are not making any New Year presents, but flight tests will start in the very near future," said Sergei Ivanov, who oversees the defense sectors of industry.

He said on December 8 the trials would begin in 2010.

Deputy Defense Minister Vladimir Popovkin has said the fighter, which has been under development since the 1990s, will enter service with the Air Force in 2015.

Russia's only known fifth-generation project is Sukhoi's PAK FA and the current prototype is the T-50. It is designed to compete with the U.S. F-22 Raptor (so far the world's only fifth-generation fighter aircraft) and F-35 Lightning II, but has yet to take to the skies.

The T-50's maiden flight has been repeatedly postponed since early 2007 for unspecified reasons.

However, in August 2009, Russian Air Force Chief Alexander Zelin said that there were problems with the engines and research was ongoing.

The PAK FA is believed to possess advanced avionics, stealth capability, a ferry range of 4,000 to 5,500 km, and endurance of 3.3 hrs; it is armed with next-generation air-to-air, air-to-surface, and air-to-ship missiles, and has two 30-mm cannons.

MOSCOW, December 23 (RIA Novosti)