TEMECULA -- Firefighters had a blaze that started Friday near the Interstate 15 Border Patrol checkpoint almost completely surrounded Sunday night, officials said.

The blaze, which burned about 150 acres, was 90 percent surrounded at about 7 p.m. Sunday, said Engineer Jeff Windham of the California Department of Forestry and Fire Protection.

He said the fire should be completely surrounded by 6 tonight, with full control expected by 8 p.m. Tuesday.

Over the past couple of days, the brush fire caused massive gridlock on I-15, especially in the southbound lanes, which were blocked to give firefighters room to get to and operate safely on the rugged hillsides where the fire was burning. The freeway remained open most of the time Sunday with traffic flowing freely, though the possibility that lanes might have to be shut down remains, officials said.

About 170 firefighters remained on the scene Sunday, Windham said. Since the blaze began at about 1:45 p.m. Friday, four firefighters have been treated for heat-related injuries, according to the fire department. The cause of the fire is still undetermined, Windham said.