Video released by the Los Angeles County Sheriff's Department showed the moment a gunman shot and critically injured two sheriff's deputies as they sat in their patrol car late on Saturday.
The footage of the incident showed the suspect approaching the parked vehicle on foot in the city of Compton and firing with a handgun through the passenger side window before running away.
The department said on Twitter: "The gunman walked up on the deputies and opened fire without warning or provocation," adding that one male deputy and one female deputy sustained multiple gunshot wounds and were in critical condition undergoing surgery overnight. The suspect is still at large.
U.S. President Donald Trump retweeted the video early on Sunday and wrote: "Animals that must be hit hard!"
Later, referring to the deputies, Trump tweeted: "If they die, fast trial death penalty for the killer. Only way to stop this!"
The sheriff's department said a few demonstrators gathered overnight outside St. Francis Medical Center in Lynwood where the deputies were being treated.
Around midnight local time, the department wrote on Twitter: "To the protesters blocking the entrance & exit of the HOSPITAL EMERGENCY ROOM yelling "We hope they die" referring to 2 LA Sheriff's ambushed today in #Compton: DO NOT BLOCK EMERGENCY ENTRIES & EXITS TO THE HOSPITAL."
It said two people were later arrested: a man who "refused to comply & cooperate" and a reporter for NPR, who the department said did not identify herself as a member of the press.
The reporter later said she was released from county jail on Sunday morning, tweeting: "I have seen [the department's] tweets and have thoughts and videos to share soon after a little rest."