FORMER National Security Agency contractor Edward Snowden has applied to extend his stay in Russia, his lawyer says.

Snowden, who is Rector of Glasgow University, has applied to Russia's migration authorities because his one-year permit is expiring at the end of July, Anatoly Kucherena said in comments quoted by Russian news agencies.

His client became stranded in a Moscow airport last year on his way from Hong Kong to Cuba, shortly after he revealed the US agency's sprawling programme.