The German government has asked the top US intelligence official in Berlin to leave the country, a Berlin lawmaker says.

The move comes amid reports of two cases of suspected American espionage in Germany and a longer dispute over alleged US National Security Agency (NSA) spying on the US ally.

German government spokesman Steffen Seibert said in a statement "The representative of the US intelligence services at the United States embassy has been asked to leave Germany".

"The request occurred against the backdrop of the on-going investigation by federal prosecutors as well as the questions that were posed months ago about the activities of US intelligence agencies in Germany. The government takes the matter very seriously". he added.

Shortly before the decision was announced, Chancellor Angela Merkel told reporters that Germany and the US had different approaches to the role of intelligence agencies.

"I think that in these times, which can be very confusing, very much depends on trust between allies" she said.

Ties have been strained between the allies since reports emerged last year that the NSA had eavesdropped on Ms. Merkel's mobile phone.

But the relationship frayed further last week when a German intelligence agency employee was arrested on suspicion of passing secret documents to the CIA.

This week a German defence ministry official was also investigated on suspicion of spying for the US.