A shooting at an In-N-Out Burger restaurant in southern Idaho on Saturday afternoon left multiple people dead and others injured, police said.

The shooter was among the dead, Twin Falls police chief Matthew Hicks said in a news conference. Police were still trying to determine the shooter’s identity and motive.

“We believe the threat to the community is over,” Hicks said.

He added that he did not yet know exactly how many were killed or wounded, and officials were still in the process of notifying next of kin. “It was a very chaotic scene.”

Before the news conference, Twin Falls county commissioner Brent Reinke said Sheriff Jack Johnson had told him five people were hurt.

Lane Koehn, 34, said he was at a stoplight near the In-N-Out when he saw a person with an AR-style rifle emerge from the drive-thru. A man with a pistol started firing at the shooter.

He then saw someone in an In-N-Out uniform drag a person bleeding from a gunshot wound in her chest across the parking lot. The employee, Koehn and the man with the pistol stayed until paramedics arrived for her.

“She was pretty bad off, but I don’t know. I hope she made it,” Koehn said.

Koehn said he was told by police to evacuate because the shooting was still active.

He also said the shooter fired at least three or four rounds and it was not clear whether or not anyone in particular was targeted.

The shooting took place near a busy shopping area and hundreds of people were there at the time, Hicks said. Police were interviewing witnesses and asked for anyone with information to contact authorities.

Reinke, who is also former prison chief for the Idaho Department of Corrections, said he learned of the incident just before 4pm and multiple agencies responded.

Police advised people to avoid the area as they closed roads.

St Luke’s Magic Valley spokesperson Taylor Marschner said in a statement that the medical centre was “working closely with law enforcement and emergency responders as they manage the situation”.

Twin Falls, a city of about 56,000 people, is about 130 miles (205km) south-east of Boise and about 75 miles (120km) north of the Nevada border.