A ferryboat has collided with a bridge in Brazil's northern state of Pará, plunging a 200m (657ft) section into the Moju River.
Witnesses said two small cars fell into the water after the ship crashed into one of the pillars.
It is unclear, however, how many people have been hurt and scuba divers are searching the river. Five crew members on the ship are said to have survived.
Pará governor Helder Barbalho signed a state of emergency after the accident.
"Our priority is searching for victims and giving complete support to their families," he told state media.
Mr Barbalho posted footage of the 860m-long collapsed bridge on Twitter.
Primeiros registros que temos sobre a queda da terceira ponte do Moju. Vou informando vocês por aqui. Neste momento sobrevoando a área com Cel. Dilson da PM, Cel. Hayman e o secretário de Segurança Ualame Machado. pic.twitter.com/OkKRMZRjBq— Helder Barbalho (@helderbarbalho) April 6, 2019
The bridge in the country's Amazon region leads to one of Brazil's busiest ports, Belém.
Authorities are working to clear debris from the river and have set up a number of barges to ferry residents across the water until it can be fixed, while placing warning signs on pillars of other bridges nearby.
Local media reported that an inspection of the bridge earlier this year revealed corrosion on the pillars. While the government requested emergency funds to fix the problem, it reportedly did not consider the issue serious enough to close the route.
Police are investigating whether the ship was officially registered, the Associated Press says.
Authorities told Reuters news agency the collapse could affect shipments of produce through northern ports.
In 2014, a vessel collided with the pillar of another bridge nearby, causing about 50m of it to collapse into the water.