Schäuble, a close ally of Chancellor Angela Merkel, told broadcaster Phoenix that the two countries intelligence services had to work together to thwart terrorist attacks, but added that did not mean America’s intelligence services could “recruit third-rate people” in Germany.
“That is just so stupid, and so much stupidity just makes you want to cry,” Schäuble said. He added that Chancellor Merkel was “not amused” by the latest spying allegations.
Merkel later said that trust was crucial between allies.
"I think that in these times, which can be very confusing, very much depends on trust between allies," Merkel said, mentioning crises such as the Syria conflict and the threat of terrorism. "More trust can mean more security."
Schäuble's comments came on the day prosecutors searched the home and office in Berlin of a second man suspected of spying for the US.
According to the Süddeutsche Zeitung, the man worked for the German Ministry of Defence and Welt newspaper reported he was a German soldier.
The US government remained silent over the reports, but the search was confirmed by Germany’s federal prosecutor. They seized his computer which will now be examined.
Last week, an employee of Germany’s Foreign Intelligence Service, the BND, was arrested near Munich, accused of selling documents to the CIA.
German lawmakers vented their anger during a visit to Washington on Wednesday and criticized perceived indifference on the spying issue in the United States.
"We find that our interlocutors have very little awareness of the problem," Norbert Röttgen, chairman of Germany's parliamentary foreign affairs committee, told journalists after talks with members of Congress and national security officials.
Röttgen complained that his delegation did not receive "answers" about the recent spying scandal, warning that the US intelligence activity in Germany could lead to a "frozen conflict" in the transatlantic relationship.