German police say a Muslim convert attacked officers with a box cutter while shouting "Allahu akbar" after they were called to her apartment in the western city of Essen.

Police spokesman Marco Ueberbach said Tuesday the officers found flags with symbols of the Islamic State group after they overpowered the 53-year-old woman. The officers were called to her apartment Monday because she was throwing furniture from a window.

She didn't open the door, so officers broke it down. They overpowered the woman and used pepper spray when she attacked them with the box cutter. None of the officers was hurt.

Ueberbach said the assailant was taken to a psychiatric clinic, and investigators were also looking into a possible extremist background.