UPDATE: All power has been restored as of 3:30 a.m.. However, Com-Ed is still investigating the cause.

ROCKFORD (WIFR) -- More than 2,000 ComEd customers were in the dark Tuesday night on Rockford's southeast side.

ComEd spokesman Paul Callighan says the lights went out around 11:00 p.m. for an unknown reason and 2,061 people lost power for about a hour.

As of 12:45 a.m. 150 people were still left in the dark. ComEd is working to restore power as quick as possible and they are looking into what sparked the outage.