UPDATE: Colorado Springs Utilities tweeted around 9:45 p.m. that power has been restored and that the outage was due to equipment failure.

More than 4,500 Colorado Springs Utilities customers were in the dark Sunday night as crews worked to restore electricity to a wide swath of southwestern Colorado Springs.

The power was out in an area west of Interstate 25 bounded by South Nevada Avenue and Cimarron Streets. Utilities reported the power failure at 9:30 p.m. on Twitter.

The utility said it expects to have the lights back on by 1 a.m.

No cause for the power failure was given.

Track the outage at csu.org.