Eleven men were injured Sunday morning after a large, four-wheeled, wooden shrine-shaped Danjiri festival float overturned in Sakai, Osaka Prefecture, according to the municipal fire department.

Those hurt in the incident, whose ages range from their teens to their 40s, were taken to hospital and were all conscious after the event, with three of them suffering serious injuries, including fractures, the department said. Osaka police officials said they are investigating in detail what caused the accident.

The Danjiri float, which was being pulled by a large group of people, lost its balance when it made a right turn at an intersection. The left side of its roof collided with a road sign, causing the float to topple.

The aftermath was chaotic with screaming spectators, locals said.

Takashi Kubo, who was aboard the float and in charge of controlling it, said the accident occurred immediately after it departed from a nearby Shinto shrine. On Sunday, the float was showcased after it was repaired.

"The speed may have been too fast" and the float was "pulled by too many people," Kubo said.