They said in a statement they had searched an Islamic culture center, detained several people for identity checks and arrested one person in connection with the measures. A spokesman for the police declined to give further details.
"Since yesterday evening the authorities in Bremen have indications, based on knowledge from the police, the domestic intelligence agency and a federal authority, of an increased threat from Islamist extremists," the police statement said.Earlier this month a carnival parade in the northern German town of Braunschweig was canceled at short notice due to a threat of an Islamist attack. (Reporting by Scot W. Stevenson and Ralf Bode; Writing by Michelle Martin; Editing by Ralph Boulton)