A former head of German intelligence on Wednesday warned against sharing sensitive material with Austria, amid growing fears over the close links between senior Austrian ministers and Russia.

The warning comes amid concerns that a police raid on the headquarters of Austria’s BVT domestic intelligence agency earlier this year in which secret files were seized may have been politically motivated.

“Caution is necessary with a service which cannot protect its own secrets or the sources and sensitive information of its partners,” said Auguste Hanning, a former head of Germany’s BND foreign intelligence service.

Other Western intelligence agencies have already stopped sharing information with Austria in the wake of February’s raid on the BVT, the Washington Post claimed in a report last week.

“There is of course now extreme caution when sharing information,” Mr Hanning told Germany’s Bild newspaper.

“It is essential for the international intelligence cooperation that all sides can be sure their sensitive information is secure with a partner service. Secrecy must be maintained. That is of course incredibly difficult when you have such a situation in Austria.”

There was widespread shock when police raided the BVT’s main offices in February and took away classified files in plastic bags and open boxes.