Turkey summoned the German ambassador in Ankara on Monday over a report in magazine Der Spiegel that Germany's BND intelligence agency had been spying on its NATO ally for years, a Turkish foreign ministry official said, according to Reuters.

The German magazine reported at the weekend that Berlin had identified Ankara as a top surveillance target in an internal government document from 2009.

Turkey's acting foreign ministry undersecretary Erdogan Iscan met German Ambassador Eberhard Pohl to voice Turkey's concerns about the report, the official said, without giving further details.

A German government spokeswoman, asked by reporters whether Turkey was a friendly nation which should not therefore be the target of spying, replied: "Germany cooperates closely with Turkey in many different areas."

A German foreign ministry spokesman confirmed that the ambassador was invited to discuss the issue by the Turkish government, but disputed that he had been "summoned".

Germany is Turkey's largest trading partner in the EU and is also home to some three million Turks, the largest diaspora in Europe.