Twenty people were injured when an escalator at a Tokyo convention center jerked to an abrupt halt Aug. 3, knocking down dozens, police and paramedics said.

Around 60 people fell backward on the 30-meter escalator when it suddenly shook and then started moving in the opposite direction at the Tokyo Big Sight convention hall, said Masafumi Shigeta, a Tokyo Fire Department official. The seriousness of the injuries was limited because people fell onto one another.