A large fire broke out Sunday afternoon in Rosemead, drawing a response of more than 100 firefighters, authorities said.

Two single-story commercial buildings caught fire in the 9000 block of Garvey Avenue, according to a Twitter post from the Los Angeles County Fire Department, and crews battled the blaze for several hours before it was knocked down.

It was unclear what sparked the fire, and the Fire Department did not immediately return messages seeking comment Sunday.

More than 100 firefighters had responded to the fire by 4 p.m., trying to keep the flames from spreading to other buildings. No firefighters or civilians were injured, according to the Fire Department’s Twitter posts.

About 5:30 p.m., the Fire Department tweeted that crews were still at the scene and would be “in defense mode for some time” at the three-alarm blaze. About 7:20, an official post saying the fire had been knocked down was accompanied by an image of heavy construction equipment among piles of rubble.

The stretch of Garvey Avenue where the fire broke out is a commercial corridor, lined with strip malls, restaurants and shops, near the Rosemead-El Monte border.