LOS ANGELES — Authorities were continuing to search Monday for a gunman who walked up to a parked sheriff's squad car and opened fire, critically wounding two Los Angeles County deputies in an ambush recorded on surveillance video. 

Officials asked for the public's help in identifying the gunman in a weekend ambush after officials offered a $100,000 reward for information leading to an arrest. 

The 31-year-old female deputy and 24-year-old male deputy underwent surgery after the shooting Saturday evening and were expected to recover, Los Angeles County Sheriff Alex Villanueva said Sunday. 

"They performed in an admirable fashion in spite of grave adversity," Villanueva said during a conversation with local religious leaders. "God bless them." 

The deputies, who graduated together from the sheriff's academy 14 months ago, were shot while sitting in their patrol car at a Metro rail station and were able to radio for help, the sheriff said. 

The department has faced criticism during recent protests over racial unrest but it's unclear if that was a factor in the shooting. Officers have only a "very, very generic description" of the shooter to go on, officials said. 

Surveillance video shows a person approach the parked patrol car on foot and shoot with a handgun through the passenger-side window.

"The gunman walked up on the deputies and opened fire without warning or provocation," the department stated.

An extended version of the video reviewed by the Los Angeles Times shows the shooter running away in the direction from which he came. He turns a corner out of the frame, past a second figure lingering on the sidewalk, according to the Times. It's unclear if the second person was involved in the attack. A Sheriff's Department spokeswoman declined to comment, citing the ongoing investigation.

Moments after the shooting, the passenger door opens and a deputy stumbles out, hand on head, according to the newspaper. The driver's-side door opens soon after. 

The video sparked reaction from President Trump who responded on Twitter: "Animals that must be hit hard!"

"This cold-blooded shooting is unconscionable and the perpetrator must be brought to justice," Democratic presidential candidate Joe Biden tweeted. "Violence of any kind is wrong; those who commit it should be caught and punished."

A handful of protesters gathered outside the hospital where the injured deputies were being treated. The protesters tried to provoke deputies stationed outside and at one point were prevented from entering the emergency room, Bishop Juan Carlos Mendez with the Churches in Action group told the TV station KABC. 

"Unacceptable behavior. The hospital should be a sanctuary, we should leave hospitals alone," he said. Mendez and members of his group gathered nearby in prayer for the wounded deputies. 

Videos from the scene recorded at least one person in the crowd yelling, "I hope they … die."

A radio reporter who was near the protest scene was taken into custody. The sheriff's department later tweeted that the reporter interfered with the arrest of a male protester.

"The female adult, who was later identified as a member of the press, did not identify herself as press and later admitted she did not have proper press credentials on her person," the department stated.

After being released, Josie Huang, a reporter for public radio station KPCC, a National Public Radio affiliate, said on Twitter that she had been covering the sheriff's news conference when she returned to the hospital after hearing protesters shouting. She was wearing her press pass, she said. 

One of several videos Huang said she shot moments before her arrest showed two men carrying red, black and green flags and yelling at deputies outside the hospital while a few other people stood by recording on their cellphones. 

Huang tweeted that she began walking behind deputies who were following the small group of protesters. 

"I was filming an arrest when suddenly deputies shout 'back up.' Within seconds, I was getting shoved around. There was nowhere to back up," Huang said on Twitter. In another video, Huang can be heard shouting, "I'm a reporter… I'm with KPCC" as she falls to the ground. 

The executive editor of the station, Megan Garvey, expressed outrage over the arrest and said her reporter appeared to be wearing her credentials and had shouted her KPCC affiliation. NPR's Editorial Director Nancy Barnes said the network was "appalled" by the arrest of a reporter doing her job. 

The office of the Los Angeles County Inspector General, which oversees investigations and actions of the sheriff's department, has opened an investigation into the reporter's arrest. 

Protesters have railed against the LA Sheriff's Department for weeks over recent shootings by deputies, including the killing of a man on a bicycle last month. There was no known connection between the recent shootings and Saturday's ambush and investigators are "chasing all leads," Villanueva told the Times. 

"Of course, there's an important conversation going on about policing in this country, but these are folks who put their lives on the line for us, and we will find justice for them," Los Angeles Mayor Eric Garcetti said on CNN Sunday.