A shroud of mystery has surrounded American whistleblower Edward Snowden's whereabouts since he received temporary asylum in Russia last week, but migration authorities have let slip that he is not in Moscow.

On Tuesday, Snowden's lawyer, Anatoly Kucherena, said the National Security Agency leaker had registered his place of residence with the authorities, as all foreigners must do, but did not divulge the location out of concern for his safety.

A migration service official said on Friday, however, that Snowden had not submitted documents to register in the capital.

"We don't have these records. I don't have any such information. He's not in Moscow," said Olga Kirillova, head of the Moscow branch of the federal migration service, news agencies reported. The service said that everyone's registration was confidential and that only Snowden or his lawyer can reveal his place of residence.

Meanwhile Snowden's father, Lon, has submitted all the necessary documents for a visa to visit Russia and plans to come in August. Kucherena told journalists earlier this week that Snowden will set a date for his first meeting with journalists after his father arrives.

Snowden is waiting to make decisions about his future until his father and lawyers get to Russia, Kucherena added.

Since he arrived in Moscow from Hong Kong on 23 June, Snowden has only been spotted in public once, when he left the airport on 1 August with Kucherena and WikiLeaks staffer Sarah Harrison.

Countless attempts by journalists to smoke him out of hiding in the airport's transit zone and capsule hotel were unsuccessful, leading to speculation that he was being hidden in a special area or even an FSB country house outside of Moscow.

Snowden commented on Friday on the closure of the encrypted email service Lavabit, which he himself has used in the past.

He told Guardian columnist Glenn Greenwald that the decision by Lavabit's owner to shut it down rather than comply with US court orders to provide access to its users' content was inspiring, and asked why internet titans like Google and Facebook "aren't fighting for our interests the same way small businesses are".