Germany has taken the unusual step of asking the CIA station chief in Berlin to leave the country, after two reported cases of suspected US spying.
Thursday's move reflects growing impatience in Germany at what is perceived as US nonchalance about being caught spying on a close ally, amid a yearlong row over eavesdropping by the National Security Agency.
"The representative of the US intelligence services at the United States embassy has been asked to leave Germany," Steffen Seibert, a German government spokesman, said in a statement.
"The request occurred against the backdrop of the ongoing 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."
Seibert said Germany continued to seek "close and trusting" cooperation with its Western partners, "especially the United States".
Shortly before the decision was announced, Angela Merkel, the German chancellor, said Germany and the US had "very different approaches" to the role of intelligence agencies.
Merkel stressed the need for greater trust between allies, a position she has repeatedly voiced since reports last year that the National Security Agency eavesdropped on her mobile phone.
In separate cases over the past 10 days, one man has been arrested and an investigation against another has been launched on suspicion that they worked for foreign intelligence.
German media have reported that the men were suspected of passing secrets to Thomas de Maiziere, the German interior minister, and reported that the scope of the cases and who was involved were not yet clear.
Talks were taking place with the US at various levels, the media reports said.
"If the situation remains what we know now, the information reaped by this suspected espionage is laughable," de Maiziere said in a statement.
"However, the political damage is already disproportionate and serious."
Al Jazeera's Nick Spicer, reporting from Berlin, said resentment had grown in Germany since October, when it was revealed that Merkel's phone was tapped and that the NSA had also plugged into Google and Facebook to spy on ordinary Germans.
"The psychology here is just one of complete resentment towards what is seen as American interference in ordinary lives and, from a governmental perspective, a complete lack of trust," he said.