LONDON >> A 73-year-old man from Britain died and dozens of people were injured after a plane encountered “sudden extreme turbulence” about 10 hours into a flight from London to Singapore, officials said Tuesday.

The plane, a Boeing 777-300ER operated by Singapore Airlines, was diverted to Bangkok, the airline said in a statement, and landed at 3:45 p.m. local time Tuesday.

In all, 71 people, including passengers and crew members, were injured, a hospital in Bangkok said. The hospital, Samitivej Srinakarin, said that of the 71 people from the flight who were being treated in its medical network, six were injured seriously. It listed four of the injured as being from Britain, with three from Malaysia, two from New Zealand and one each from Ireland, Spain and the United States. Other victims’ nationalities were not known.

The remaining passengers and crew were examined and treated at Suvarnabhumi Airport in Bangkok, the airline said. Singapore’s Ministry of Transport said it was examining the episode and would send investigators to Bangkok, and the National Transportation Safety Board in the United States said it would send a representative and four technical advisers to help. The Thai prime minister said his government would “assist with everything necessary for the injured.”