Lonnie Snowden said he had been asked several weeks ago about Edward, who is sought by the US for leaking details of electronic surveillance programmes.

However, he wants to know the FBI's intentions, he told Russian state TV.

He said his son would not get a fair trial in America and, if he were in his son's place, he would stay in Russia.

He described his son as a "true patriot" who had "made America a more democratic country" by revealing secret details of the US National Security Agency's surveillance programmes.

The interview was broadcast live, early in the morning, on the Russia 24 news channel. Mr Snowden spoke English, with a Russian translation.

Mr Snowden has been stuck in transit at a Moscow airport for more than a month as he has no valid travel documents.

'Forever grateful'

"Edward, I hope you are watching this," Lonnie Snowden said in the interview.

"Your family is well. We love you. We hope you are healthy, we hope you are well, I hope to see you soon, but most of all I want you to be safe. I want you to find a safe haven."

The fugitive's father also thanked the Russian authorities for keeping his son safe.

"I also would like to thank President Vladimir Putin and the Russian government for what I believe to be their courage and strength and conviction to keep my son safe," he said.

"Like any mother or father who loves their child, I love my son and I will be forever grateful for what you have done, very much."

Edward Snowden arrived in Moscow's Sheremetyevo Airport on 23 June from Hong Kong, where he had made his revelations.

He has requested temporary asylum in Russia, while saying he hopes eventually to go to Latin America..

The Snowden affair has caused diplomatic ructions around the world, upsetting America's close allies and traditional enemies.

The US Attorney General, Eric Holder, has given Moscow an assurance that he will not face the death penalty if extradited to America, but the Russians say they do not intend handing him over.