Dozens of people in a southeastern Brazilian were injured when a sidewalk next to a river collapsed just after Christmas lights were illuminated as the main attraction of a popular holiday season event, officials said.

The 21 adults and 12 children who fell Monday evening had gathered in Joinville in the state of Santa Catarina to take part in the city’s annual Christmas festival, city officials said in a statement.

They were taken to hospitals and all had been released by Tuesday morning, the statement said. None suffered serious injuries.

The stretch of sidewalk next to the Cachoeira River collapsed minutes after the Christmas lights were turned on, the statement said.

It was not immediately clear whether the people fell into the river istelf or onto a river bank below the raised sidewalk that serves as a walkway next to the river.

Video images showed people at the event pulling other people out of the hole caused by the sidewalk collapse.