German authorities said Wednesday that they had arrested a British citizen and accused him of spying for Russia while working at the British Embassy in Berlin.

The man, identified only as David S., is suspected of passing documents to Russia for money since at least November. He reportedly worked as a local hire.

The British government confirmed the arrest but said in a statement it would “not be appropriate to comment further as there is an ongoing police investigation.”

German Foreign Ministry spokesman Christofer Burger said the German government was monitoring the incident.

“We take the indications that the intelligence activity of the arrested man was carried out on behalf of a Russian intelligence service very seriously,” Burger said. “Spying on a close ally on German soil is not something we can accept.”

Officials with the Russian Embassy had no comment on the case, according to Interfax.