The father of US intelligence leaker Edward Snowden arrived early Thursday in Moscow, hoping to meet his son for the first time since the latter became a fugitive.

Lon Snowden arrived at Moscow's Sheremetyevo airport, where his son had spent more than a month in transit limbo before Moscow agreed to grant him temporary asylum in August.

"I'm here to learn more about my son's situation," he told journalists at the airport. "My hope is to learn more about his circumstances and his health and to discuss legal options."

"If the opportunity presents itself, I certainly hope that I have the opportunity to see my son," Lon Snowden said in televised remarks.

He was met at the airport by Snowden's Russian lawyer, Anatoly Kucherena, who said he will be hosting Lon Snowden as his "guest". Kucherena said they have not yet decided how long the elder Snowden will stay in the country.

Lon Snowden said he had had no direct contact with his son in recent months, and said he didn't yet know what his plans were. "I really have no idea what his intentions are," he said.

"I'm not sure that my son will be returning to the US," he told journalists. "That's his decision, he's an adult."

He said he believed his son is not leaking information from Moscow. "Edward Snowden, since he has been in Russia, is simply trying to remain healthy and safe," the father said.

"I have extreme gratitude that my son is safe, secure, and free" in Russia, he said, repeating that he believed his son to be a "whistleblower" rather than a criminal.

The visit of Lon Snowden, a US Coast Guard veteran who lives in Pennsylvania, was long mulled, and he reportedly received a Russian visa in August.

He had told US media in July that he was approached by the FBI with an offer to fly to Russia in order to persuade Edward Snowden to come home but refused due to uncertainty about whether he would have direct communication with his son.

Kucherena said Thursday that Snowden will meet with his father soon, but that the date and place will be kept secret. He also said that Snowden's mother was also interested in coming to Russia.

"As far as the arrival of other relatives, there is such interest, but it will be decided later," Kucherena said.

Snowden flew in to Moscow on June 23 from Hong Kong with a revoked US passport and remained in the transit area for weeks, as Russia mulled US requests to hand him over.

He finally walked out of the airport on August 1 after obtaining temporary asylum in Russia despite protests from Washington and has remained underground ever since.

On Monday a tabloid Russian website LifeNews published a blurry photograph of a man it said was Snowden rolling a cart of groceries out of a supermarket.

The 30-year-old former National Security Agency contractor is wanted by the United States after revealing to the media details of massive domestic and foreign surveillance programmes operated by the secretive agency.

His lawyer Kucherena has said he is living in a secret location in fear of being tracked down by the United States.