A power outage struck the Richmond District, Laurel Heights and Presidio Heights neighborhoods in San Francisco tonight, affecting more than 3,600 customers, according to PG&E.

The outage, which took place around 9:27 p.m., affected 3,660 customers north of Geary between Lyon Street and 24th Avenue, PG&E spokesman J.D. Guidi said.

Power was restored to most customers before 10:30 p.m., Guidi said.

The outage has been attributed to an underground equipment failure.

Traffic lights on Pine Street between Octavia and Fillmore streets, and on Arguello were affected by the outage, and Muni buses on Clement and California were delayed, according to sources at the scene.

An officer answering the phone at the Richmond District Police Station said the station had received one or two phone calls about the outage shortly before 10 p.m.

California Pacific Medical Center said it was not affected by the outage.