We are asking (the appeals court) to overturn the verdict and cease the criminal case

Lawyer Ivan Pavlov

Mr Pasko was convicted of treason after passing footage of the navy dumping nuclear waste into the Pacific Ocean to a Japanese television company.

The former navy captain was arrested in 1997 and accused of divulging state secrets on Russia's Pacific Fleet.

Following a series of trials and appeals, he was found guilty on Tuesday at a closed military court in Vladivostok of high treason.

Lawyer Ivan Pavlov told the Reuters news agency an appeal had been lodged with the Russian Supreme Court.

Quarantine

"We are asking (the appeals court) to overturn the verdict and cease the criminal case," he was quoted as saying.

Mr Pavlov said the defence would file its appeal after it had studied the 1,000 pages of files from the trial.

Pasko is now being held in quarantine

Another lawyer, Anatoliy Pyshkin told Russian NTV that Mr Pasko had been taken to a remand centre.

"We have little chance of seeing him today," he said on Wednesday.

During sentencing, the court rejected prosecution demands for a nine-year prison term as Pasko's actions did not greatly harm the state.

At his first trial in July 1999, Pasko - a journalist with the Russian Pacific Fleet's newspaper - was convicted only of abuse of office and given a three-year sentence. He was immediately set free under a prisoner amnesty.

But he appealed to the military section of Russia's Supreme Court to clear his name entirely. Prosecutors also lodged an appeal.

'Environmental abuses'

The Supreme Court overturned the verdict of his original trial and said he should be retried on the espionage and treason charges.

This criminal case was born of a dislike for the truth

Grigory Pasko

In the latest case, Pasko was accused of handing over to Japan's NHK state television a secret document detailing a military base that held radioactive waste.

The result stunned Pasko who had expected to be cleared after highlighting the case for media freedom.

Pasko has said he is being punished for reporting on environmental abuses by the navy

In a closing statement made earlier this month at the trial, Pasko admitted being critical of his country but denied betraying it.

'Spy mania'

"This criminal case was born of a dislike for the truth," he said, according to a copy of the speech.

Pasko claims charges are revenge for his reporting

Human rights campaigners had also hoped to see a change in official attitudes towards ecological whistleblowers.

US Consul General James Shoemaker, who was in court to observe "a case for human rights", said the decision was "a bit unexpected".

Pasko has accused Russia of "spy mania", accusing the Federal Security Service (FSB) of persecuting people like himself to justify their existence.

There has been a spate of similar cases since former FSB chief Vladimir Putin became President of Russia.