BERLIN (AP) -- German authorities are investigating a second spy case reportedly involving the U.S.
Federal prosecutors said Wednesday that police raided properties in the Berlin area on "initial suspicion of activity for an intelligence agency."
Daily Sueddeutsche Zeitung reported the man worked in "the military field" and is suspected of spying for the United States.
A 31-year-old German intelligence employee was arrested last week on suspicion of spying for foreign powers since 2012. German media have reported he spied for the United States and offered his services to Russia.
The case has frayed relations between Berlin and Washington already strained by reports last year that the National Security Agency spied on Chancellor Angela Merkel's cellphone.
A German official said the U.S. ambassador in Berlin went to the Foreign Ministry in Berlin Wednesday.