One man died and another was seriously injured during a fight in Temecula over the weekend, which involved an off-duty Costa Mesa police officer, authorities said.

According to Riverside County sheriff’s Deputy Craig Roberts, the fight started at a Mexican restaurant around 7:20 p.m. Saturday and spilled onto Main Street in Old Town entertainment district, the Associated Press reported.

The name of the off-duty Costa Mesa police officer has not been disclosed. He later told investigators that others attacked him and that he identified himself as a police officer, pulled a handgun and started firing, Roberts said. All three men involved in the altercation were immediately taken to a local hospital where one of them died. The officer was treated for non-life threatening injuries. He is currently resting at home, according to Sgt. Stephanie Selinske of the Costa Mesa Police.

About 60 people were having dinner inside the restaurant when the shooting began outside, Carlos Puma, owner of Bank of Mexican Food restaurant said.

“It was terrifying, absolutely. We actually got everyone down on the ground until it was over and the police got here,” he added.

The Costa Mesa Police Department said its internal affairs investigators would review the incident, but the officer had not been suspended.