A Russian court sentenced a senior lecturer at an aviation institute to 20 years in jail on Friday after finding him guilty on treason charges, it said, the latest in a series of such cases.

The Moscow City Court said it had found A.G. Vorobyov guilty of illegally exporting technology or technical information that can be used to develop weapons. RIA news agency identified him as Alexei Vorobyov and said he worked at the Moscow Aviation Institute.

He was also found guilty of involvement in contraband of weapon parts, the court said. It did not disclose further details of the offences. The trial was held behind closed doors.

Interfax news agency cited a source as saying Vorobyov denied the charges.

A number of Russian scientists, soldiers and officials have been charged with treason in recent years, accused of passing sensitive material to foreign countries.

Critics of the Kremlin say the arrests are often the result of unfounded paranoia and complain the charges cannot be scrutinised because of their classified nature.

The Interfax news agency reported last week that an academic studying aerodynamics had been detained on suspicion of state treason for allegedly passing secrets to a NATO country.

Russia also sentenced a former state official to 12-1/2 years in prison for treason last week.