Police in central Germany say they have detained two known Islamic extremists in an investigation of possible plans for an attack.

Police said the men — a 27-year-old Algerian and a 23-year-old Nigerian, whose names weren't released — were detained during searches early Thursday in and near Goettingen. They said both live in the city and have long been part of the Salafist scene there.

Twelve properties were searched in the operation. Goettingen police chief Uwe Luehrig said that information about a possible attack plan had accumulated in recent days to the extent that officials decided to take quick action.