A $100,000 reward was offered Sunday in the hunt for a gunman who brazenly walked up to a parked patrol SUV and shot two Los Angeles County sheriff's deputies multiple times in what officials described as an ambush-style attack.

Both sheriff's deputies were initially "fighting for their lives" at St. Francis Medical Center in Los Angeles following the Saturday night shooting outside a Metro train station in Compton.

On Sunday, a senior Los Angeles County sheriff's official told ABC News the deputies are expected to survive.

"That was a cowardly act," Sheriff Alex Villanueva said during a news conference on Saturday night.

"The two deputies were doing their job, minding their own business, watching out for the safety of the people on the train.

Update: The gunman walked up on the deputies and opened fire without warning or provocation. pic.twitter.com/cBQjyKkoxJ

— LA County Sheriffs (@LASDHQ) September 13, 2020

To see somebody just walk up and start shooting on them. It pisses me off. It dismays me at the same time. There's no pretty way to say it."

One of the wounded law enforcement officers, a 31-year-old mother of a 6-year-old boy, was shot in the jaw and arms and is listed in critical but stable condition, according to the senior sheriff's officials.

Her 24-year-old partner suffered gunshot wounds to his forehead, arms and a hand, but was alert, the official said.

Both deputies underwent surgery about 8 p.m. Saturday, officials said.

Villanueva said he swore both deputies in as members of the sheriff's department 14 months ago.

The Los Angeles County Board of Supervisors on Sunday authorized a $100,000 reward for information leading to the arrest and conviction of the gunman.

Sheriff Villanueva Discusses Ambush Shooting of Two Deputies in Compton. To watch the full press conference, please visit https://t.co/fOaVP5wTUe pic.twitter.com/7gXlbLQpAK

— LA County Sheriffs (@LASDHQ) September 13, 2020

The shooting unfolded about 7 p.m. local time on Saturday as the sheriff's deputies sat in their marked patrol car near the Martin Luther King Jr. Transit Center, authorities said.

Surveillance video released by the sheriff's department showed an individual dressed in black shorts, a dark jacket and wielding a pistol in his hand walk up to the patrol vehicle and open fire without warning through the passenger-side window.

The shooter, who authorities said is believed be Black and 28 to 30 years old, ran away to a black four-door sedan and sped away.

As the gunman fled, the surveillance video showed the patrol vehicle's passenger-side door open and one of the wounded deputies stumble out.

"Moments ago, 2 of our Sheriff Deputies were shot in Compton and were transported to a local hospital," the Los Angeles County Sheriff's Department tweeted shortly after the apparent unprovoked attack.

"They are both still fighting for their lives, so please keep them in your thoughts and prayers."

Villanueva did not identify the deputies by name.

Numerous sheriff's deputies and officials went to St. Francis Medical Center and stood vigil outside the hospital.

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. People's lives are at stake when ambulances can't get through.

— LA County Sheriffs (@LASDHQ) September 13, 2020

L.A. County Sheriff's Department in an update overnight confirmed that an unlawful assembly was declared as protesters blocked the entrance and exit to the area hospital emergency room.

Two arrests were made including a female member of the press along with an adult male.

"After deputies issued a dispersal order for the unlawful assembly of a group of protesters blocking the hospital emergency entrance & exits, a male adult protester refused to comply & cooperate," the Los Angeles County Sheriff's Department said in a tweet.

"During his arrest, a struggle ensued at which time a female adult ran towards the deputies, ignored repeated commands to stay back as they struggled with the male and interfered with the arrest.

"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. Both individuals have been arrested."