Multiple people have been injured, some seriously, after a bus left Hwy. 39 south of Mackenzie, BC, Wednesday, prompting a major emergency response and the closure of the highway.Mackenzie RCMP said officers were called to the crash Wednesday after receiving reports that a bus had gone off the roadway, 180 north of Prince George.Police confirmed multiple injuries, including serious injuries, but have not released the number of people involved or the extent of their injuries.RCMP officers, BC Emergency Health Services and local fire rescue crews responded to the scene.Multiple ambulances were requested, and an air ambulance was dispatched to assist with transporting injured passengers.Hwy. 39 south of Mackenzie was closed as emergency crews worked to treat those injured and investigators began examining the crash scene.Police warned the highway could remain closed for several hours, with no alternate routes available around the closure.“We ask the public to avoid the area and allow emergency personnel the space they need to safely respond to this incident,” said RCMP spokesperson Cpl. Brett Urano.“Drivers should expect significant delays and are encouraged to check DriveBC before travelling.”.Highway maintenance crews were also called in to assist with traffic control while emergency responders worked at the scene.RCMP collision analysts have been requested to investigate the circumstances surrounding the crash.Police have not said what caused the bus to leave the highway or whether weather and road conditions may have contributed.The type of bus involved and the number of passengers aboard have also not been disclosed.Investigators said the incident remains in its early stages and additional information is limited.Motorists planning to travel along Hwy. 39 are being urged to monitor DriveBC for updates on the closure and avoid the area until emergency crews have completed their work.