Electricity was knocked out for about 6,000 Near North Side residents Monday night.

Customers began reporting the outages about 8:30 p.m. across the Old Town and Gold Coast neighborhoods, a ComEd spokeswoman said. Crews were working to figure out the cause.

As of 9:30 p.m., the number of outages was down to about 2,500, according to the utility company’s online map. Report outages at 1-800-EDISON-1.