Several emergency vehicles have been called to an incident on the upper floors of The Bell Hotel.
An East Anglian Air Ambulance car, and two East of England Ambulance Service vehicles were parked outside the hotel pub on Castle Meadow and Farmers Avenue.
An East of England Ambulance Service spokesperson said: 'We were called at just before 12.09pm on March 5 to a report of an incident on Orford Hill in Norwich.
'A rapid response vehicle, ambulance and a response car from the East Anglian Air Ambulance treated a man in his 60s who was unresponsive and has been taken to the Norfolk & Norwich University Hospital for further care.
'The patient's condition is believed to be life-threatening.'
Staff declined to comment.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here