Civil Defense sirens accidentally went off overnight on Maui and Oahu.
The first siren sounded in Pearl City at about 1 a.m. Friday.
Civil Defense was unable to turn it off remotely, so the Honolulu Fire Department was called in to manually deactivate it.
On Maui, a siren went off in Lahaina at about 3:30 a.m.
When Maui Civil Defense tried to turn it off, they accidentally set off a siren in Kihei.
The state Civil Defense will investigate the cause of the malfunctions.