A patient being transported in an ambulance was airlifted to hospital in critical condition Tuesday afternoon following a collision with a farm tractor east of Beiseker.Airdrie RCMP Integrated Rural officers responded to the crash at approximately 1 p.m. near the intersection of Hwy. 9 and RR 254.Police said the collision involved an ambulance travelling with its emergency equipment activated and a farm tractor. Both vehicles were travelling on Hwy. 9 when the crash occurred.The male patient inside the ambulance suffered critical injuries and was transported by STARS Air Ambulance to hospital.The two emergency medical personnel aboard the ambulance — the driver and a paramedic who was attending to the patient in the rear compartment — were also injured in the collision.Both EMS workers were transported to hospital by ground ambulance with serious injuries. RCMP said they were listed in stable condition.The circumstances leading to the collision have not been released.Hwy. 9 remained closed in the area Tuesday afternoon as RCMP investigators and Occupational Health and Safety officials examined the scene.Motorists were advised to avoid the area and seek alternate routes while the investigation continues.RCMP have not indicated when the highway is expected to reopen.