Justice Minister Heiko Mass told the Passauer Neue Presse on Friday that the US should now “wipe the slate clean” over spying in Germany, adding the United States needed a "clear stop signal".
Germany ordered the US spy station chief to leave the country on Thursday after months of frustration at the lack of cooperation by the US to clear up the NSA spying scandal, and the uncovering of two alleged US spies working in German intelligence and the Ministry of Defence.
“The Americans must now actively help clear up the allegations,” Maas said. “This includes a clear statement on any other cases of espionage which we may not know about yet. Above all, we need a firm assurance from Washington that these activities have finished once and for all.”
Foreign Minister Frank-Walter Steinmeier said on Friday he would discuss the transatlantic spy row with US Secretary of State John Kerry when both attend Iran nuclear talks in Vienna this weekend.
Bild newspaper reported on Friday the spy chief now had 72 hours to leave Germany.
It said the US Ambassador in Berlin, John Emerson, was phoned at 11.30am on Thursday by the Foreign Ministry and told either the station chief left the country voluntarily or the secret service head would be officially expelled.
According to Bild newspaper, Merkel’s office envisages far-reaching consequences over the alleged espionage cases.
The tabloid reported on Friday that German intelligence was limiting cooperation with their US partners to the “bare essentials”, such as work concerning the safety of German soldiers in Afghanistan and terrorist threats.
News site Spiegel Online called the expulsion a "diplomatic earthquake". It pointed out that such measures were usually reserved for "pariah states" such as North Korea.
There are few precedents for such dramatic measures between Nato members. Among the latest was France's decision in 1995 to send home several US officials for spying on its territory.
Defence Minister Ursula von der Leyen, known as a champion of close US ties, said it was right Berlin had "sent a very clear signal that it will no longer tolerate this kind of breach of trust and that we need a fresh start with each other".
Interior Minister Thomas de Maizière said the benefits of the alleged US spying, which have done huge diplomatic harm, were questionable. "Based on what we know now, the information gained through this alleged espionage is ridiculous," he said.
Sounding like a man in a difficult relationship, de Maizière told broadcaster ARD on Thursday night: “At some point there needs to be good times [in the US-German relationship].
"Today we have taken a reasonable and sober measure which takes into account what has happened in the past few months," he added.
But leader of left party Die Linke, Katja Kipping, claimed the unprecedented step was only “cosmetic”.
“We expect the federal government to present a concerted action plan against US spying in Germany by the end of the summer break at the latest,” she said.
Her party colleague and deputy chairman of the parliamentary committee which oversees the intelligence services, André Hahn, called once again for a “no spy” agreement with the US as a “sign of goodwill”.
Shortly before the expulsion was announced, Merkel said that "common sense tells us that spying on one's allies...is a waste of energy. We have so many problems that we should, in my view, focus on the essentials."
The chancellor said she saw "a very different approach" on both sides of the Atlantic "as to what the job of the intelligence services is...after the end of the Cold War".
She mentioned common threats for the allies, such as the Syria conflict, and said effectively dealing with them "depends on trust between allies...More trust can mean more security."
Finance minister Wolfgang Schäuble, meanwhile, described US spying on Germany as being so “stupid” it made him want to cry.
SEE ALSO: Germany expels US spy station chief