One San Diego police officer was killed and another was injured Thursday night in a shooting as they tried to make a stop in the city, police said.
A suspect also was shot and is in custody. He's being treated at a hospital for a gunshot wound, San Diego police Chief Shelley Zimmerman told reporters Friday morning.
Police are trying to determine if anyone else was involved in the shooting in southern San Diego and asked residents nearby to stay inside as they searched.
Details about the shooting were sparse. Zimmerman said the two officers, both members of the department's gang suppression unit, radioed shortly before 11 p.m. that they were going to stop someone.
Almost immediately afterward, they called for emergency backup, Zimmerman said. She didn't say why the officers were trying to make a stop.
"I'm extremely heartbroken to report that we had an officer shot and killed," Zimmerman said.
Asked whether the shooting was an ambush, the chief said it wasn't clear.
"We don't have enough information at this point," she said.
The names of the officers and the suspect weren't immediately released.
The injured officer, shot in the upper torso, underwent surgery at a hospital and is expected to survive, the police department tweeted Friday morning.
Zimmerman said officers who responded to the pair's call for help made a heroic attempt to save the life of their other colleague, rushing him to a hospital in a squad vehicle.
"(There were) heroic efforts by the officers on scene, heroic efforts by the doctors to save his life," she said.
The officer who died had a wife and two children, Zimmerman said.
Officers' shooting deaths up 79% from this time last year
Thursday's violence comes as this year's shooting deaths of U.S. law enforcement officers outpaces those of 2015.
As of Friday, 34 U.S. law enforcement officers had died from shootings in 2016, a 79% increase from the total in the same period last year, according to the National Law Enforcement Officers Memorial Fund, which keeps data on officers killed on the job.
Many of this year's deaths came during a summer of heightened tensions between law enforcement and the communities they serve after civilian cameras captured the shooting deaths of Alton Sterling in Louisiana and Philando Castile in Minnesota at the hands of police.
Among the officer deaths this summer were the July 17 killings of three officers in Baton Rouge, Louisiana, and a July 7 attack in Dallas that killed five officers.
Annual rates of officer shooting deaths have fluctuated over the past 10 years. The decade's highest total came in 2011, with 73 officers shot dead.
Firearms were responsible for 41 of 123 officer fatalities in 2015, according to the memorial fund, but it was not the No. 1 cause of death. Traffic-related incidents, such as automobile and motorcycle crashes, caused 48 deaths.
So far in 2016, gun-related deaths are the leading cause, followed by 24 traffic-related fatalities.