Al-Qaida and associated groups were believed to be planning an attack on the German parliament's seat - the Reichstag in Berlin, Der Spiegel reported on Saturday.
According to the report, the groups planned to take hostages and "perpetrate a bloodbath" using firearms. The cell planning the attack was supposedly comprised of one German, a Turk, a man from North Africa and an unknown suspect.
The attack was planned to take place in February or March. Authorities said that intelligence about the plot was behind Wednesday's announcement by the German Interior Ministry of an imminent attack, according to the Spiegel report.