SAN FRANCISCO (AP) — Two people are in the hospital with what police described as life-threatening injuries after being shot early Sunday by a San Francisco police officer who opened fire when a person pointed what turned out to be an air-powered gun.

The trouble started around 2 a.m. Sunday after a group of people left a bar in the city’s Mission District and were involved in altercation with a second group, said Officer Gordon Shyy, a department spokesman.

Officers responded when one person ran to a nearby police station and told authorities there was a person brandishing a gun. The two people — one of them the suspect with the gun —were shot by the officer after he opened fire when he saw the suspect pointing the gun at the group, Shyy said.

“The officer discharged his firearm in order to preserve the safety of those people,” Shyy said.

Police have not said how many shots were fired by the officer, but Shyy said it was “multiple.” The names of the two people shot or specific details of their wounds or conditions had not been released by late Sunday afternoon, and police had not released any information about the second person.

Police initially described the weapon as a replica gun, but later said it was an air-powered firearm “capable of discharging a projectile,” such as air-soft or paintball gun.

Investigators will conduct testing to determine exactly what type of projectile the gun was designed to fire and if it was operable, Shyy said.

After the shooting, a number of people were detained at the scene and were being interviewed by investigators.

One area resident told KTVU-TV that he wished there were more police on the streets of the neighborhood, especially on weekend nights.

“I think it would be a great idea to be able to go out in the evening and not have to worry about whether or not you’re going to be involved in a shooting that has nothing really to do with you,” Joseph Yoye told the station. Homicide investigators were investigating the incident, as they handle all officer involved shooting incidents.

Officials from the San Francisco District Attorney’s Office and the Office of Citizen Complaints were also investigating, which is standard protocol, Shyy said.

The officer would be placed on paid administrative leave, which is also standard procedure.

Police Chief Greg Suhr also planned to hold town hall meeting later this week to discuss the shooting, Shyy said.

The incident is the second shooting in two days in the San Francisco Bay area in which police fired weapons at suspects armed with either an air-powered or replica gun.

On Friday, Oakland police shot and wounded a burglary suspect after he came out of a West Oakland home with what was later determined to be a fake handgun.