The main hospital in Bristol was evacuated, witnesses said, after a power cut caused what was described as a “critical incident”.
One person there said at least three fire engines rushed to the Bristol Royal Infirmary, in Upper Maudlin Street.
Police officers on horseback were seen asking people to leave the area.
Other hospitals in the city were also affected.
University Hospitals Bristol and Weston NHS wrote on social media: “We have declared an internal critical incident due to a power outage affecting a number of our hospitals in Bristol city centre.
“We are asking the public not to attend our hospitals until the incident is resolved. Please use alternative services in the area.”
Patients and visitors to the Royal Infirmary who had to get out were forced to wait outside.
BristolLive said it had been told that the hospital lost power before the first alarm was heard, and that that the road outside the hospital had been closed.
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