The suspect and another person were injured and taken to a hospital, police Lt. Jennifer Amat said, adding that there was no ongoing threat to the public, NBC News reported.
Police said officers arrived to an active shooting scene about 5:30 p.m.
There was a shooting involving an officer, police said, but more details were not immediately clear. The officer was not injured, Amat said.
Amat did not know the conditions of the suspect or the other injured person. Police were expected to release more information Wednesday night.
The building appeared to have several offices. Amat did not say where the victims were found, but said of the incident, "as far as we know it was an actively evolving situation, so it was not contained to just one area."
Gov. Gavin Newsom called the events "horrifying and heartbreaking," and said in a statement that "our hearts are with the families impacted by this terrible tragedy tonight."
“I’m deeply saddened by reports of a mass shooting in Orange County, and I’m continuing to keep victims and their loved ones in my thoughts as we continue to learn more," she said in a statement. "My team and I will continue to monitor the situation closely.”
The federal Bureau of Alcohol, Tobacco, Firearms and Explosives were responding, a spokesperson for the Los Angeles field office said.
Orange is a city of about 140,000 people, 30 miles southeast of Los Angeles.
MAH/PR
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