Police in the German city of Bremen warned Saturday of a potential danger from Islamic extremists there and stepped up security measures and said they had increased their presence in the city centre and stepped up protection of the Jewish community.
Officials received indications of an elevated risk from violent Islamic extremists on Friday evening, police in the northwestern city said in a statement. They gave no further details of the nature of the potential threat.
They said in a statement Saturday they had searched an Islamic culture centre, detained several people for identity checks and arrested one person in connection with the measures.
"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.
Police said they stepped up their presence in the city and, as a precaution, increased security for the Jewish community.
The warning comes amid heightened concern in Europe about terrorism following attacks this year in Paris and Copenhagen.
In mid-February, police in the northern German city of Braunschweig canceled a Carnival street parade over fears of a terrorist attack.