Investigators in Germany are demanding that the U.S. clear up accusations that a man working in German intelligence was really spying for the CIA. The man was arrested on suspicion of spying by officials Friday.

"I expect everyone now to assist quickly in clearing up the accusations -- and quick and clear statements from the USA too," Thomas de Maiziere, the Interior minister, told Bild newspaper.

According to initial reports, the 31-year-old man, whose name remains unreleased, passed classified documents and other information on German agents to the U.S. for a span of two years while he worked in Germany's BND intelligence service. The man is suspected of providing 200-300 documents in total, traveling to Austria and handing the information to American intelligence via USB flashdrive. In exchange, the man received payments of 25,000 eruos (about $34,000).

The man was caught when he attempted to sell similar information to the Russians, and his emails were intercepted. When his property was searched, a USB stick was found containing sensitive material.

Upon further inspection, the man's computer also held a guised weather app installed to enable communication with his U.S. contacts. The link was activated when the user searched for New York weather.

After questioning the man about being a Russian mole, he admitted to being a double agent for the U.S. He also told German investigators that the Americans were specifically interested in an ongoing parliamentary inquiry into the NSA.

This discovery strains already tense relations between Germany and the U.S. Many Germans are still upset about the NSA's phone tapping of Chancellor Angela Merkel. Despite German efforts to contact U.S. officials for an explanation, there are no confirmed responses from the CIA or other government agencies.

Spiegel magazine reported that this latest discovery "could end in a fatal rift with the U.S." over security cooperation.