German Chancellor Angela Merkel said on Monday allegations that a German man worked as a double agent for US intelligence were serious and, if true, were a clear contradiction of what cooperation between partners is supposed to be about.

She made the comments at a news conference while on a visit to Beijing.

The White House and State Department have so far declined to comment on the arrest of a 31-year-old employee of Germany's BND foreign intelligence agency.

According to intelligence and political sources, the man admits to passing documents to a US contact.

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