A passerby discovered an unexploded World War II mortar round in a plastic bag in a trash can at Cartwright Field in Makiki yesterday morning, causing police to close off streets in the area for about an hour.

Honolulu Police Department’s bomb squad was dispatched to the city park after a man reported finding the potential explosive device at 8:50 a.m.

Police closed Lunalilo Street between Keeaumoku and Kewalo streets, Keeaumoku Street from Beretania Street to Wilder Avenue, and Kinau Street from Keeaumoku Street to Makiki Street until the device was removed.

The 81 mm mortar round was taken to Schofield Barracks for disposal by Army ordnance experts and the roads re-opened at 10 a.m., police said.

Its destruction was done by soldiers from the 706th Explosive Ordnance Detachment assigned to the 45th Sustainment Brigade.