German authorities have arrested a German man on suspicion of being a double agent for the United States. The man has been linked to spying on a panel investigating activities by the National Security Agency in Germany.

The man's name was not released. But the 31-year-old reportedly worked for Germany's BND foreign intelligence agency and is suspected of providing the U.S. with information about a German parliamentary panel set up to investigate allegations that the NSA spied on German lawmakers, including Chancellor Angela Merkel.

If the allegation proves true, it would likely put more strain on relations between the two allies.

Though Reuters reported that the alleged spy didn't have direct access to the German NSA panel, he reportedly offered to provide information to the U.S. and sold the American government several documents pertaining to the committee investigation of the NSA for $34,100.

The State Department declined to comment on the matter. A spokesperson for Merkel said the espionage allegations were very serious.

The German authorities made the arrest on Wednesday and Chancellor Merkel and President Barack Obama talked by phone Thursday night. Their conversation supposedly centered on violence in Ukraine and it is unclear whether they discussed the latest spying accusations against America.

German officials initially arrested the alleged double agent on suspicion that he was spying for Russia before the man reportedly admitted otherwise.

Officials in Berlin requested a "no spy" arrangement with the U.S. in the wake of the revelations of NSA spying last summer. But American officials reportedly did not concede.

According to the Wall Street Journal, the German Foreign Ministry summoned the U.S. ambassador about the incident.