AURORA, Colo. (AP) — Three students were shot Friday during a fight in the parking lot of a high school in the Denver suburb of Aurora, the police chief said, only days after six teenagers from a nearby campus were shot and injured at a park.

All of Friday’s injuries were not life-threatening, and police were trying to determine whether any of the three who were hospitalized were involved in the shooting, which broke out shortly before 12:30 p.m. in the parking lot of Hinkley High School, Chief Vanessa Wilson said.

Wilson said “multiple shooters” were involved and that a school resource officer fired a shot during the fracas and also applied a tourniquet to one of those wounded, she said. No weapons were recovered, she said.

Two of those shot were taken to a hospital, and the third managed to get to a hospital on their own, police said. Two were students at Hinkley and the third from APS Avenues School, which serves students grades 7-12, Wilson said.

The shooting followed another Monday in which six students from Aurora Central High School were the victims of bullets fired from a car driving by. Police have not arrested anyone yet. The two schools are 3 miles (4.8 kilometers) apart.

Wilson said police were working to determine if the two shootings were related.

The victims in Monday’s shooting, boys and girls ranging in age from 14 to 18, were all expected to survive. Wilson said Tuesday that two of them had “significant” injuries and faced long recoveries.

Numerous shell casings fired from different guns were found at the scene of Monday’s shooting and it is possible some rounds were fired by someone on foot, police said. Police have said they have located one of two cars involved in that shooting.

As she did on Monday, Wilson expressed frustration that too many guns are in the hands of too many students, and she pleaded with parents to help a police department under pressure to stem the wave of violence among young people.

“People know what happened here. This cannot continue. These kids have guns and they got them from somewhere,” the chief said. “I need the parents’ help on this.”

Wilson said all Aurora public schools would be closed through the Thanksgiving week holiday.

KCNC-TV obtained cellphone video that the TV station said was taken from a car inside the parking lot as shots were being fired. A youth in the vehicle is heard saying, “Oh, no. No, no, no,” and seen crouching as the shots continue ringing out.

Gov. Jared Polis said he was thinking about the injured people in the hospital — and added that the back-to-back shootings are a message that action is needed to curb violence among young people.

“We as a state have to redouble our efforts on public safety,” said Polis, a Democrat.

He added that “with the two shootings in Aurora we are going to have a renewed focus on youth violence.”

Nearly two hours after the shooting, yellow crime tape surrounded the parking lot and anxious parents waited outside the campus to be reunited with their children.

As students were allowed out of the building, television images showed them walking calmly and hugging parents.

Numerous shell casings fired from different guns were found at the scene of Monday’s shooting and it is possible some rounds were fired by someone on foot, police said. Police have said they have located one of two cars involved in that shooting.