German authorities said on Thursday they had arrested an employee of the foreign intelligence service BND, on suspicion of the person sharing state secrets with Russia this year and thereby committing treason. Police arrested the suspect, a German citizen identified as Carsten L, on Wednesday, in Berlin, the federal prosecutors office said, adding that the police also raided his flat and workplace as well as those of another person. “The accused is suspected of state treason,” federal prosecutors said in a statement. “In 2022, he shared information that he came by in the course of his work with a Russian intelligence agency. The content is considered a state secret.” German authorities have warned of likely heightened Russian spying given the Kremlin’s stand-off with the west over its invasion of Ukraine. The German government expelled 40 Russian “spies” in April, according to the domestic intelligence agency. The Russian embassy in Berlin did not immediately reply to Reuters’ request for comment. The BND began its own, far-reaching, internal investigation into the matter as soon as it became aware of the possibility of treason within its own ranks, Bruno Kahl, chief of the organisation, said in a statement. When these suspicions firmed up, the BND called in federal prosecutors. Kahl said that discretion was key in going forward, as any detail of the investigation made public could give the “opponent an advantage in its intent to harm Germany”. He said: “With Russia we are dealing with an actor where we must reckon with its ruthlessness and willingness to be violent.” The BND would not be giving out any further details on the case until federal prosecutors had concluded their investigation, Kahl added. The case came days after Austria said it had identified a 39-year-old Greek citizen whom it suspected of spying for Russia. The last time a German intelligence employee was arrested for treason was in 2014, although then it was for betraying secrets to the US Central Intelligence Agency. The man, identified as Markus R, was, in 2016, sentenced to eight years in prison. At the time the episode cooled relations between the close allies Berlin and Washington.