BERLIN (AFP) - A German lawmaker who met US intelligence leaker Edward Snowden said on Friday the fugitive had told him he would be ready to testify to the US Congress to shed light on "possibly serious offences".

"Mr Snowden didn't appear to me as anti-American or an enemy of America or some such," Hans-Christian Stroebele, an opposition Greens party deputy told reporters.

"Quite the opposite," he added, a day after a surprise meeting with Mr Snowden in Moscow over his allegation that Washington tapped Chancellor Angela Merkel's phone for years.

"He has always emphasised, also to my question whether he is ready to give information before the German Parliament in Germany... that first he would prefer to present the facts in front of the US Congress, before a committee of the US Congress and explain," Mr Stroebele said.

"He sees his message in the US as not only shedding light on undesirable developments but possibly serious offences and says he can do that, he's in the position to," he added.

Mr Snowden is also ready to talk in Russia to German prosecutors investigating US espionage practices, his lawyer said on Friday.

Washington has revoked Mr Snowden's passport and demanded his extradition to face criminal charges in the United States for leaking top-secret documents about the National Security Agency's activities.