A fire has broken out the Christie Hospital in Manchester, one of the largest cancer treatment centres in Europe.
Roads around the hospital in Withington in south Manchester have been cordoned off as firefighters try to get the blaze under control.
Video from the scene captured huge black plumes of smoke pouring from the Paterson Building, a research facility next to the NHS hospital.
The building is home to the Cancer Research UK Manchester Institute, part of the University of Manchester.
The research centre has been evacuated and witnesses said clinical staff and admin staff had gathered outside the burning building.
No details were available as to how to the fire had started, or what the financial cost of the damage was likely to be.
A university spokesperson said: “The fire service was called to an incident at The Paterson Building on Wilmslow Road at 10.36 this morning.
"Everyone has been evacuated safely from the building and the university is supporting the emergency services in managing the incident.”
A spokeswoman for the Christie NHS Foundation Trust said no patients in treatment wards had been affected, but those attending the research facility had been evacuated from the building.
The spokesperson said: "All the associated areas have been evacuated including any patient areas. The fire service is on site.
"For staff and patients if they have not already been evacuated they need to carry on as normal. ...
"The fire service has informed us that the fire on the roof is believed to be under control. They are doing an internal review to ensure that the fire is completely extinguished."
Firefighters are tackling the blaze well at The Christie #christiehospita
Cancer Research UK spokeswoman Jane Bullock said the extent of damage to the building and the likely cost of repairs were not immediately clear.
“The fire broke out in the roof of the Cancer Research UK Manchester Institute which adjoins The Christie on Wilmslow Road," she said. "All staff were safely evacuated. We are awaiting further information from the emergency services about the extent of the damage caused by the fire which broke out this morning.
“The Cancer Research UK Manchester Institute is a leading cancer research institute, based within the University of Manchester, which is core funded by Cancer Research UK.
“Last year, Cancer Research UK spent around £22million on research carried out in Manchester. Research spans the whole spectrum of cancer research, and also focuses on some hard-to-treat cancers, such as pancreatic and lung cancer.”
A spokesperson for Greater Manchester Fire Brigade said: "At 10.36am on Wednesday the fire service was called to a building fire at Christie Hospital, Wilmslow Road, Manchester.
"Firefighters are wearing breathing apparatus and using jets and hose reels to extinguish a fire involving a three-storey office block and labs."
The fire brigade spokesperson added: "Crews are working hard to tackle a fire involving the first floor plant room and roof space of the Cancer Research UK Institute Manchester building on the hospital site.
"The affected building has been safely evacuated and other office buildings nearby have also been evacuated. Currently, no buildings containing patients are being evacuated."
Six fire engines and an aerial ladder were dispatched to the scene.