Former US spy agency contractor Edward Snowden applied for temporary asylum in Russia today after spending three weeks at a Moscow airport trying to avoid prosecution in the United States on espionage charges.

The White House said Mr Snowden is "not a dissident" and should be expelled and returned to the United States to face trial.

Mr Snowden is seeking refuge in Latin America after leaking details of US government surveillance programmes, but has not risked taking any flight that might be intercepted by the United States.

He flew into Moscow from Hong Kong on 23 June.

"He reached the conclusion that he needs to write an application for temporary asylum [in Russia], and this procedure has just been done," Anatoly Kucherena, a lawyer who met Snowden on Friday along with human rights activists, said.

"For now he is not going to go anywhere. For now he plans to stay in Russia," he said.

If Mr Snowden were granted temporary asylum, Mr Kucherena said, he should have the same rights as other citizens and be free to work and travel in Russia.

The asylum application could end Mr Snowden's time in limbo but risks deepening US-Russian tensions.

Russia has refused to expel him to his homeland but has also kept him at arm's length, saying he has not crossed its border because he remains in the international transit zone at Moscow's Sheremetyevo airport.

President Barack Obama's administration repeated its call for Russia to send Mr Snowden, 30, back to the United States.

"He is not a human rights activist, he is not a dissident. He is accused of leaking classified information," White House spokesman Jay Carney said.

"He is a United States citizen who has been charged with crimes, and ... he should be afforded every bit of due process here in the United States. And he should return here to face trial."

Unlike political asylum, granting Mr Snowden temporary asylum would not require a decree from President Vladimir Putin, who may hope it is the best option for minimising the damage to US ties without looking weak in the eyes of Russians.

The Kremlin sought to distance Mr Putin from the asylum decision, which is formally up to immigration officials but is widely expected to be in the president's hands.

"If we are talking about temporary asylum, this is an issue not for the president but for the Federal Migration Service," Mr Putin's spokesman, Dmitry Peskov, told reporters in the Siberian city of Chita.

The head of the FMS, Konstantin Romodanovsky, confirmed the agency had received Mr Snowden's application.

Anti-secrecy group WikiLeaks, which has been helping Mr Snowden, said on Twitter that he had applied for "a temporary protection visa".

Mr Snowden, 30, is trapped in the transit zone of Sheremetyevo airport, an area between the runway and passport control which Russia regards as neutral territory.

He said on Friday he would seek refuge in Russia only until he can travel to one of the three Latin American countries ready to give him political asylum - Venezuela, Bolivia and Nicaragua.

He said the United States and its allies were preventing him from reaching those countries.

The US has revoked Snowden's passport and urged other countries not to help him reach an asylum destination.

Mr Kucherena said he expected a decision on Snowden's asylum request "soon", though the FMS has up to three months to decide on the application.

Temporary asylum is granted for up to a year, with the possibility of extension.

After Mr Snowden met lawyers and activists at the airport on Friday, many pro-Kremlin politicians went on state television to say Russia should grant him asylum.

"He fears torture or the death penalty may be applied to him [if extradited]," said Mr Kucherena, who said he had been advising Mr Snowden since the airport meeting.