Customs authorities in Russia's Far East have launched a criminal case against a Chinese citizen who attempted to smuggle spare parts for Russian MiG-29 and Su-27 fighters last year, a customs' spokesperson said on Friday.

The man, whose identity has not been revealed, was caught at one of the border checkpoints in Transbaikal region in July last year. Customs officials found six stepping motors, two piston pumps, 54 connectors, an elapsed-time meter and other parts in the trunk of his car.

"It took experts from the Defense Ministry almost a year to prove that the confiscated equipment is part of assembly kits for MiG-29 and Su-27 fighter jets," Yulia Philipova said.

"A criminal case has been opened," she said.

It is the second attempt by Chinese nationals to smuggle spare parts for fighter jets from Russia in the past three years.

A Chinese man was detained at the same border checkpoint in 2009 while trying to smuggle power supply circuits for Su-27s.

China is notorious for producing copycat versions of military equipment from all over the world.

Russia has accused China of producing its own clones of some Russian-made weaponry, including the Su-27SK fighter jet, in violation of intellectual property agreements.