TUCSON, Ariz. (AP) — Authorities say power has been restored to most of the 5,500 Tucson Electric Power customers on the city's northwest side.

Company officials say the main areas affected Thursday were Catalina, Cortaro and Casas Adobes.

They say power was restored by 3 p.m. Thursday to all but about 400 customers.

The cause of the outage wasn't immediately disclosed.