Police in Berlin continued to question two men of Middle Eastern origin on Friday, suspected of buying chemicals for a bomb attack.
The 24-year-old German-Lebanese man and a 28-year-old Palestinian were held following a raid on an Islamic cultural centre in the German capital.
The arrests come just days ahead of the 10th anniversary of the September 11th terrorist attacks on America.
“Officials have been carrying out investigations for many months based on the suspicion that a large attack was being prepared,” said Berlin police spokesman Thomas Neuendorf.
Later, police searched the suspect’s homes and removed several boxes.
Forensic scientists are attempting to identify a suspicious liquid seized during the raids.
Until now Germany has been spared a major terrorist attack by al Qaeda-linked groups.
But on Wednesday a 21-year-old Kosovan Albanian confessed to the murders of two US airmen at Frankfurt airport in March, claiming he’d be influenced by islamist propaganda.