A Russian nuclear weapons expert has been found guilty of spying for the US, Russian news agencies report.
Sutyagin says any information he provided was in the public domain
A closed military trial convicted Igor Sutyagin of passing on information on nuclear submarines and missile warning systems to the Americans.
Investigators claim he sold the information to a British company that
was a cover for the CIA.
But Sutyagin says he was only writing analysis based on publicly available sources.
Sutyagin - a senior weapons control researcher at Moscow's respected USA-Canada Institute - says he had no reason to believe the company was an intelligence cover.
His sentence has not yet been announced but he could face up to 20 years in prison.
Sutyagin's lawyer Boris Kuznetsov criticised the conduct of the trial and accused the presiding judge of manipulating the jury.
"The questions addressed to the jury did not correspond to the charges," Mr Kuznetsov was quoted by Russia's NTV television as saying.
The lawyer said he would be appealing against the verdict.
In January, four international human rights groups said that Sutyagin was "the target of politically-motivated treason charges", and urged the Parliamentary Assembly of the Council of Europe to appoint a rapporteur on his case.
"Sutyagin's case is part of a pattern of arbitrary prosecutions of independent scientists, journalists and environmentalists in Russia who work on sensitive topics," the four groups - including Amnesty International and Human Rights Watch said in a statement.
Correspondents say the case has alarmed the scientific community, and prompted fears of a resurgence of Soviet-era KGB tactics.
Sutyagin's trial is believed to be the first espionage case in Russia to be decided by a jury.
Sutyagin has been in prison since his arrest in October 1999.
A court had been expected to deliver a verdict in the case in February 2001, but instead instructed prosecutors to continue investigating and left Sutyagin in jail.
Mr Sutyagin's trial is one of a series of high-profile spy cases against Russian researchers.
In December, Valentin Danilov - a scientist accused of spying for China - was cleared of all charges.
Last year, military reporter Grigory Pasko was imprisoned for treason after disclosing how Russia dumped nuclear waste in the Pacific Ocean was released on parole.
Pasko, a former naval officer, was sentenced to four years in jail in 2001.