Smoke was rising from an encampment fire in San Francisco's Bayview District on Friday morning, after a fire erupted at what's being described as a "treehouse" that was built into a hillside beside the Caltrain tracks.

The fire was first reported at 11:30 a.m. Friday, and crews responded from the San Francisco Fire Department as well as Caltrain and the San Mateo County Sheriff's Department, which serves as law enforcement for Caltrain. The fire broke out at a homeless encampment beside the train tracks near the 1800 block of Oakdale Avenue.

SFFD spokesperson Lt. Jonathan Baxter posted video from the scene after the fire was tamped down, and he described "a treehouse into a hillside with a ground-level encampment that encroached on a grass area" as being the source of the fire. "We're now focused on some really heavily insulated trees and artifacts from the encampment," he said, saying that firefighters were using both water and foam to make sure the fire was completely extinguished.

With hoses running across the tracks, Caltrain service was suspended in both directions while the firefight continued.

Baxter added that members of the Homeless Outreach Team and SFFD paramedics were on the scene to make sure that residents of the encampment were able to receive city services. No injuries were reported, and no "standard brick and mortar structures" were damaged in the fire, Baxter said.