Some sort of sidewalk collapse occurred Thursday morning over a utility trench near the Lower Haight neighborhood, trapping one person underground.

The San Francisco Fire Department undertook a rescue effort near the intersection of Divisadero and Oak streets Thursday morning. A collapse occurred just before 10:30 a.m., and the SFFD's public information officer, Captain Jonathan Baxter, tweeted that there was one person trapped under an estimated eight feet of dirt.

The nature of the trench or what kind of construction or other activity had been going on there is not clear. Firefighters were pictured in the area focused on the sidewalk and street just outside a garage, where they were digging to remove dirt. The garage can be seen below, between two Victorian buildings on the 1100 block of Oak Street.

Motorists are being told to avoid the area, and traffic is backing up on both Oak and Divisadero.

ABC 7 has live helicopter footage of the rescue effort.

Update: According to Captain Baxter, a "sidewalk collapse occurred during utility construction work."

Update 2: Baxter confirmed as of around 12:15 p.m. that rescuers had reached the trapped individual, and he was deceased. The operation then transitioned into a body-recovery effort.

The nature of the work that was being performed in the trench and by whom has not yet been reported.