An elderly patient has died and two paramedics have been injured trying to save him, after an ambulance burst into flames at a hospital in Ireland.
Emergency services said the fire broke out in the year-old vehicle as the man was being taken to the emergency unit at Naas General Hospital in Co Kildare.
The man, believed to be about 70, was in the back of the ambulance when the blaze happened at about 1.30pm and witnesses reported hearing a loud bang.
Investigations are centring on an oxygen tank exploding.
One of the paramedics, believed to be in his 30s, was said to be fighting for his life after suffering 70% burns.
He was initially treated at the scene before being taken to the specialist burns unit in St James's Hospital in Dublin for treatment.
His colleague, believed to be around the same age, suffered less serious injuries.
Union representatives said the two men had tried to save the patient as the ambulance burst into flames.
Siptu organiser Paul Bell said: "Both of them tried to get the patient out.
"We are convinced that the paramedic crew attempted everything possible to contain the situation and save the patient. They did their duty."
Other medics and ambulance staff at the hospital are understood to have reported that one of the paramedics was in the back of the vehicle trying to get the patient out when he suffered severe burns and his colleague went in to rescue him.
The casualty department was shut down following the incident.
Witness Rob Moore was inside the hospital when the fire alarm sounded and rushed out after hearing a bang.
"I don't know what actually happened, but the whole thing just went up," he said.
"As I came out of the door of the hospital I could see two paramedics at the back (of the ambulance), one of them was really severely burnt.
"I think there was a fireman there, who was off-duty, he started to get things under control.
"Everyone was pulled away from it then."
Mr Moore said he did not hear an explosion but believed he heard a bang or a thud.
He also saw someone he believed to be one of the paramedics being taken to an area outside the hospital, where medics stripped him down to treat his wounds.
The Health Service Executive (HSE) said patients were diverted away from Naas for several hours after the incident and the National Ambulance Service put appropriate diversion protocols in place.
A number of fire crews from Co Kildare attended the scene.
Investigations were launched into the cause of the fire by the HSE, Fire Service, Garda and Health and Safety Authority.
Ambulances normally carry up to six sealed cylinders of different types of potentially flammable gas to treat patients at a scene and while transporting them.
They carry oxygen and also an analgesic gas and air mix for pain relief.
Michael Dixon, chairman of the National Ambulance Service Representative Association (NASRA), offered condolences to those caught up in the incident.
"Our thoughts and prayers are with the man who lost his life in the back of the ambulance," he said.
"But we are also concerned for the two paramedics injured as well."
Mr Bell added: "We would like to express our deepest sympathy with the family of the patient who died and our grave concern for the two paramedics who tried in vain to save his life.
"This tragedy should never have happened."