At least nine dead and hundreds missing after dam collapse in Brazil
Rescuers are searching for survivors in a huge area of south-eastern Brazil buried by mud after the collapse of a dam holding back mining waste.
At least nine people are dead and up to 300 more are missing after the disaster in Minas Gerais state.
State governor Romeu Zema said: "Most likely, from now on we are mostly going to be recovering bodies."
Workers with Brazilian mining company Vale were eating lunch on Friday afternoon when the dam collapsed, unleashing a sea of reddish-brown mud that knocked over and buried several structures belonging to the company.
The level of devastation in the city of Brumadinho and surrounding areas quickly led President Jair Bolsonaro to describe it as a "tragedy".
Vale CEO Fabio Schvartsman said he did not know what caused the collapse, and confirmed that about 300 employees were working in the area when it happened. About 100 have been accounted for, and rescue efforts are under way to determine what had happened to the others.
Mr Schvartsman told a news conference that "the principal victims were our own workers", adding that the restaurant where many of his staff ate "was buried by the mud at lunchtime".
After the dam collapsed in the afternoon, parts of Brumadinho were evacuated, and firefighters rescued people by helicopter and ground vehicles.
Local television channel TV Record showed a helicopter hovering inches off the ground as it pulled people covered in mud out of the waste.
Photos showed rooftops poking above an extensive field of the mud, which also cut off roads. The flow of waste reached the nearby community of Vila Ferteco and a Vale administrative office, where employees were present.
Another dam administered by Vale and Australian mining company BHP Billiton collapsed in 2015 in the city of Mariana in Minas Gerais state, resulting in 19 deaths and forcing hundreds of people from their homes.
Considered the worst environmental disaster in Brazilian history, it left 250,000 people without drinking water and killed thousands of fish.
An estimated 60 million cubic metres of waste flooded rivers and eventually flowed into the Atlantic Ocean.
Mr Schvartsman said what happened on Friday was "a human tragedy much larger than the tragedy of Mariana, but probably the environmental damage will be less".
Mr Bolsonaro, who assumed office on January 1, said he has sent three cabinet ministers to the area.
"We will take all the possible steps to minimise the suffering of families and victims," Mr Bolsonaro said in a speech, which he posted on Twitter.
The president plans to tour the area later. The far-right leader campaigned on promises to jump-start Brazil's economy, in part by deregulating mining and other industries.
Environmental groups and activists said the latest spill underlined a lack of regulation.
The rivers of mining waste raised fears of widespread contamination.
According to Vale's website, the mine waste, often called tailings, is composed mostly of sand and is non-toxic. However, a UN report found that the waste from the 2015 disaster "contained high levels of toxic heavy metals".