US whistleblower Edward Snowden has applied to extend his stay in Russia, his lawyer has said.

Anatoly Kucherena told the AP news agency on Wednesday that Snowden applied to Russia's migration authorities "a long time ago".

His one-year permit will expire at the end of July.

Kucherena refused to say what kind of migration status Snowden was seeking, and said it was up to authorities to make the decision.

Snowden flew into Moscow last, shortly after revealing the NSA's sprawling programme of tapping phones.

He received asylum in Russia, attracting the ire of the US.

Snowden has never been seen in public in Russian and has never spoken to local journalists. His whereabouts inside Russia are unknown.

A Kremlin-connected website has published several pictures of Snowden indicating that he either lives in Moscow or visits it often.

Source: Associated Press