The person, whose name has not been released, was shot dead, Salt Lake County Sheriff Rosie Rivera told a news conference. Both deputies were taken to hospital for treatment.
One deputy is in a stable condition after being shot in the face and the other one is in a critical condition after being shot in the eye.
The delegates were part of a campus security team in jail when an altercation began in a grassy area at the parking lot around 10:30 a.m., Rivera told reporters.
Rivera said it was unclear what led to the quarrel. An officer-involved critical incident team was called in to investigate the shooting, she said.
“These types of incidents are really devastating for the department. And we hope and pray that our deputies will be fine,” Rivera said.
“The law enforcement environment is extremely dangerous at the moment and we know it,” she added.
The prison complex in the town of South Salt Lake contains the sheriff’s headquarters. The jail is under lockout following the standard protocol and roads in the area will be closed ‘for a long time’ for the investigation, Rivera said.
“It’s devastating when someone in law enforcement is in a situation like this,” she said. “For our sheriff’s deputies and our employees, this is something you do not really expect to happen on a Saturday morning.”