Former US intelligence official Edward Snowden has received a Russian passport and swore allegiance to Russia.

"Yes, he got a passport, he took the oath," Anatoly Kucherena, Snowden's lawyer, told state news agency TASS.

The 39-year-old Snowden fled into Russian exile after publicizing the mass storage and analysis of telephone and internet data by the US intelligence service NSA in 2013.

Russian President Vladimir Putin granted Snowden Russian citizenship in September.

Snowden and his wife Lindsay previously announced after the birth of their son in Russia that they would apply for citizenship to have the same rights as the child born in 2020, who received Russian citizenship automatically.

In this way they wanted to avoid being separated from their son in the future.

USA demand extradition

"I'm in Russia because the White House deliberately canceled my passport to lure me here," Snowden wrote on Twitter on Friday.

The US is demanding Snowden's extradition on charges of espionage.

"This is still a criminal investigation," White House spokesman John Kirby told reporters on Friday.