Nine people were injured when a Boeing 747 hit severe turbulence over Japan.  Two crew members and six passengers were taken to hospital after the jet landed in Hong Kong on Tuesday evening.  Another passenger who sustained an injury didn't require hospitalization.  Cable News television showed one passenger being taken away in a stretcher. 

The 747-400 flight from San Francisco, was carrying 321 passengers and a crew of 21.  It encountered the turbulence near Hokkaido around noon Hong Kong time Tuesday. 

A passenger surnamed Wu told local TV news channels he felt like he was a on a roller coaster during the turbulence, which lasted two minutes.  He said some passengers were thrown out of their seats and hit the overhead bins. 

The incident came one day after violent turbulence triggered "pandemonium" aboard a United Airlines flight in the U.S. and sent passengers and crew flying through the cabin, according to company representatives and passengers.