SAO PAULO, Dec 25 — The death toll in a Brazilian bridge collapse that occurred on the weekend rose to four yesterday, with the search for another 13 people missing made perilous by trucks with tonnes of acid falling into the water, officials said.

Three trucks — two carrying sulfuric acid and one carrying pesticides — were among eight vehicles carried down into the Tocantins River when the Juscelino Kubitschek de Oliveira bridge collapsed on Sunday.

Those heavy vehicles were transporting a total of "22,000 liters of agricultural pesticides and 76 tonnes sulfuric acid, a corrosive chemical product,” Brazil’s National Water Agency said.

It was not yet known if the acid had seeped out of the trucks and into the river. Water analyses were being carried out.

In the meantime, rescuers were operating cautiously, using boats and not sending in any divers.

River water supplies to nearby communities were also suspended.

The fire service attending the scene said four bodies had been recovered, including the woman driver of one of the acid-transporting trucks, and an 11-year-old girl.

On Sunday, a 36-year-old man was rescued alive.

The bridge, built in the 1960s and more than half a kilometre long, was the main link between Brazil’s states of Tocantins and Maranhao.

The causes of the collapse were being investigated, but initial indications were that the bridge’s central beam gave way.

The day before the collapse, a local man had published an online video showing visible cracks in the bridge and warning that there was imminent danger.

President Luiz Inacio Lula da Silva on Monday promised on the X social media platform that his federal government would provide all necessary aid in the rescue operation and the investigation.

The collapse came on top of two other deadly transport accidents in Brazil over the weekend.

The country’s worst highway accident in 17 years happened on Saturday when a bus crashed and caught on fire, killing 41 people in the southeast state of Minas Gerais.

On Sunday, a private plane crashed into the city of Gramado in south Brazil, killing a family of 10 on board. — AFP