At least two adults were killed and two persons, possibly students, were struck by gunfire in a classroom shooting on Monday at a Southern California elementary school, police and fire officials said.

San Bernardino Police Chief Jarrod Burguan said the shooting at Northpark Elementary School in San Bernardino, east of Los Angeles, appeared to a “murder-suicide” and that two wounded students had been taken to the hospital for treatment.

“We believe the suspect is down, and there's no further threat,” Mr. Burguan said in a Twitter post. He said the dead were adults.

ABC News, citing information from a police spokeswoman, earlier reported that three people, including a teacher, were hit by gunfire, in addition to the shooter.

The San Bernardino County Fire Department said in a Twitter post that there were “multiple gunshot victims” from the incident. The elementary school was being evacuated and students were being taken to a nearby high school. Aerial television footage from the scene showed students walking single-file across the campus from the school building.