Germany's foreign intelligence agency (BND) has been spying on Turkey for almost four decades, Focus magazine said on Saturday, in a report to be published next week that could further antagonize the NATO members.

The article follows revelations this week that suggested German intelligence had been spying on Turkey, but the details about the espionage go further than initially reported.

Germany's ambassador in Ankara was summoned on Monday after media reports said Berlin had identified Turkey as a "top surveillance target," quoting a government document from 2009 that confirmed Berlin had been spying on Ankara for years.

Turkey's foreign ministry immediately described the report as "absolutely unacceptable," if verified.

"It is expected that the German authorities present an official and satisfactory explanation on the claims reported by German media and end these activities immediately if the claims are true," a ministry statement read.

Turkey is apparently not the only NATO member under German surveillance: Weekly news magazine Spiegel reported on its Website Saturday that the BND also targeted Albania.

Government approval

With regard to Turkey, Focus claimed the BND had been spying since 1976 and that Social Democrat (SPD) Chancellor Helmut Schmidt had "expressly approved" the move.

The magazine also cited government sources as saying the decision to monitor Turkey - as an official mandate - had been agreed by a government working group. It allegedly included representatives of the chancellery and a number of main ministries.

A spokesman for the German government declined to comment on the Focus allegations.

Government embarrassment

The report could further embarrass Chancellor Angela Merkel's government. Berlin was lambasted with accusations of hypocrisy this week because of its outrage over allegations of US surveillance on Germans, including the tapping of the chancellor's phone.

Merkel said earlier this year that spying among friends was "not at all acceptable."

In the face of the recent allegations, however, conservative lawmaker Hans-Peter Uhl told Focus there were "good reasons" for the BND to keep its eye on Turkey, citing human trafficking, drugs and terrorism as issues of concern.

"We need to know what is coming to us from Turkey, an applicant for European Union accession," Uhl told Focus.

Germany is Turkey's largest trading partner in the European Union and home to at least 3 million Turks. Relations, however, are not always smooth. Merkel's CDU is overtly skeptical about Turkish EU membership.

glb/jr (AFP, dpa)