Three people, including an eight-month-old baby, were killed and two teenagers injured in a mass shooting during a community festival in West Valley City, a suburb of Salt Lake City, on Sunday night, authorities confirmed.

The violence unfolded at Centennial Park during “Westfest,” an annual community carnival, after an altercation broke out between two groups. According to the West Valley City Police Department, a 16-year-old boy from one of the groups pulled a gun and began shooting just as officers moved in to defuse the situation.

The gunfire claimed the lives of an 18-year-old male involved in the dispute, a 41-year-old woman who was a bystander, and an eight-month-old infant. Two other teens—a boy and a girl—were wounded, each suffering gunshot injuries to the arm. Authorities said it remains unclear whether the injured teens were involved in the confrontation.

Police officers at the scene returned fire but did not hit the suspect. The teen shooter was later apprehended and is now in custody.

The attack marks the 156th mass shooting in the United States this year, according to the Gun Violence Archive, which defines such events as those in which four or more people are shot or killed, excluding the gunman.

The tragedy has shocked the West Valley City community, with local leaders urging residents to come together and support the victims’ families as the city mourns the devastating loss.