SAO PAULO, Brazil(AFP)—A bus returning from a religious festival in northeast Brazil veered off the road on a curve and overturned on Tuesday, killing at least 16 people, including four children, officials said.

The bus had been carrying about 60 people when it tipped over in the rural interior of Alagoas state, ejecting some passengers while others were trapped underneath the wreckage.

The Alagoas regional government said in a statement seven women, five men and four children were killed in an accident that remains under investigation and was described as “highly complex.”

Local media reported that the bus had been returning from celebrations for Our Lady of Candelaria, a religious festival in the state of Ceara that attracts thousands of devotees every February 2.

“The bus went off the road on a curve, overturned, and some people were thrown out,” said Colonel Andre Madeiro, director of the Alagoas Aviation Department, which took part in the rescue operation.

“Some were trapped under the vehicle. It was a very bad accident, even atypical,” he told a press conference.

The survivors, including a seriously injured child, were taken to local hospitals, where they remain under medical care.

Alagoas governor Paulo Dantas declared three days of mourning.

“I express my solidarity with the families and friends at this time of such great pain,” Dantas wrote on X.

Deadly road accidents are frequent in Brazil. In October last year 17 people died in northeast Brazil, in the state of Pernambuco, when a driver lost control of a bus.