MOSCOW (AFP) - The Russian lawyer for Edward Snowden revealed on Thursday that the father of the former US intelligence analyst had contacted his son via the Internet in defiance of legal advice.

The 30-year-old ex-National Security Agency contractor received asylum in Russia on August 1, after spending more than five weeks stranded in a Moscow airport avoiding extradition to the United States.

Mr Snowden is wanted by Washington on espionage charges linked to his media disclosures about the secret details of US surveillance programmes.

Attorney Anatoly Kucherena said on Thursday that Mr Snowden and his father Lon had recently chatted via the Internet. Mr Lon Snowden has obtained a Russian visa and is expected in Russia soon to visit his son.

"This decision (to contact Edward Snowden) was taken by Lon Snowden independently, contrary to the recommendation of his attorneys," the RIA Novosti news agency quoted Mr Kucherena as saying.

"Fatherly feelings turned out to be stronger than security concerns," said the lawyer.

"But we still do not recommend that they communicate via the web, even using encrypted channels, although we understand that Edward is a technology expert."

The younger Snowden's stay in Moscow has been shrouded in secrecy and his current whereabouts are unknown.

The dates and other circumstances of Mr Lon Snowden's upcoming visit to Moscow have also been kept tightly under wraps.

The elder Snowden had earlier told US media that while he wanted his son to return home at some point, he did not believe that his son could get a fair trial in the US.

Mr Kucherena said that neither the Snowden family nor its attorneys would disclose the dates of Mr Lon Snowden's visit to Moscow "out of security concerns".

"This is the family's wish," Mr Kucherena said.

"When the father comes here with his lawyer and the family consultations are held, he will then be able to disclose this to reporters and answer any questions that may exist."