JOIN USQuoting police sources, Der Spiegel said the attack would involve a hostage taking in Berlin’s historic Reichstag building.
Germany’s Federal Crime Office (BKA) was informed about the plans in several telephone calls from a jihadist abroad, who allegedly wanted to quit an extremist group, the magazine said.
Information received from the caller prompted Interior Minister Thomas de Maiziere on Wednesday to warn of a heightened threat of Islamist attacks on German territory.
Barriers were erected around the Reichstag as part of increased security measures.
German police and the interior ministry were not immediately available for comment on the report.
Group of six
Der Spiegel said the attack was to be carried out by a unit of six people, according to the informer.
Two of them had already arrived in Berlin six to eight weeks ago, while the four others — a German, a Turk, a North African and another man whose identity was unknown to the informer were waiting to enter the country.
The attack was allegedly planned for February or March.
Der Spiegel said De Maiziere had been told by the FBI two weeks ago of a planned attack by a Shia Indian group which was cooperating with al-Qaeda and planning to send two group members to Germany.