The German government has confirmed the removal of Gerhard Schindler, 63, as the chief of the German foreign intelligence agency, BND. It comes as a surprise at a time when Germany faces a growing threat from Islamic State (Isis) militants.

Chancellor Angela Merkel's Chief of staff Peter Altmaier said in a statement that Schindler would be replaced by Bruno Kahl on July 1. "The BND faces major challenges over the coming years, encompassing all aspects of its work," he said.

He added: "These include the evolution of its mission in light of shifting security challenges, the upgrading of the agency on the technical and personnel front, organisational and legal consequences arising from the parliamentary investigation into the NSA and the move of large parts of the BND from Pullach to Berlin."

According to Reuters, it's not immediately clear why he is being forced out two years before he reaches his retirement age. He came under pressure last year when it emerged that the BND had gone against German interests and spied on its European partners at the request of the US National Security Agency (NSA). It strained relations between the United States and Germany.

Schindler appeared to have weathered the storm when he promised to bring agents in field offices under central control, saying that some of them have taken on "a life of their own".

German media reports suggested that officials doubted that Schindler could make the changes to the BND that Berlin felt were necessary in the two years that remained before his retirement.

In a speech on Monday (25 April) in the northern German city of Hanover, US President Barrack Obama said: "If we truly value our liberty, then we have to take steps that are necessary to share information and intelligence within Europe, as well as between United States and Europe, to stop terrorists from travelling and crossing borders and killing innocent people."

Earlier this month, the BND celebrated its 60th Anniversary. Long based in Pullach in southern Germany, it is set to move into its new headquarters in central Berlin next year.