BERLIN (AP) — German media reported Friday that police in the northern city of Hamburg arrested a suspected Islamic extremist in the summer who planned to carry out an attack.

Hamburg-based weekly Der Spiegel said a 20-year-old German-Moroccan citizen was taken into custody in August after trying to buy a weapon and a hand grenade online.

Police didn't immediately confirm details of the report, saying only that an arrest had been made in connection with breaches of firearms control laws.

Der Spiegel reported that police found chemicals in the man's possession that could be used to make explosives.