The Alberta Serious Incident Response Team, known as ASIRT, says Medicine Hat police had been investigating a domestic dispute.
As part of the case, officers began chasing a suspect vehicle along the Trans-Canada Highway.
RCMP then took over the pursuit when the vehicle left Medicine Hat city limits.
The vehicle was involved in what ASIRT says was a serious collision near Redcliff, northwest of Medicine Hat, but the group would not confirm if anyone was hurt or killed.
ASIRT says it is looking into the circumstances of the crash.
The agency reports to the Alberta Justice Department and investigates events involving serious injury or death that may have resulted from the actions of a police officer.