The man who leaked details of the secret United States Prism surveillance programme has been sacked by his employer, Booz Allen Hamilton, a consultancy firm.
Edward Snowden leaked classified details of the programme while employed as a contractor in a National Security Agency facility.
He has been in hiding in Hong Kong, but has not been seen since checking out of his hotel on Monday.
In the latest development, the Russian government said it may provide Mr Snowden with asylum if he requests it.
A presidential spokesperson in Moscow said Mr Snowden's leaks are an ideological catastrophe for the United States.
The BBC reports the Obama administration is trying to gauge what damage globally has been done.
Congress is asking for more information about the massive monitoring of phone calls and internet use revealed by Mr Snowden.
House of Representatives Speaker John Boehner said he is a traitor who has put lives at risk.
And the Civil Liberties Union has filed a lawsuit challenging the legality of the NSA programme.