A collapse of a disused dam at an iron-ore mine complex in southeast Brazil killed at least seven people and left 150 missing, officials said, as they sought to evaluate the full scope of the disaster.

The tailings dam, owned by Brazilian mining giant Vale, broke apart “very violently, very suddenly,” sending a massive torrent of mud over the complex where 300 mine employees were working, Vale CEO Fabio Schvartsman told a news conference in Rio de Janeiro.

The deluge rumbled on to the nearby town of Brumadinho, located southwest of the city of Belo Horizonte, cutting a swath through vegetation, farmland and roads, and impeding access to the area.

The death toll was expected to go higher, as rescue teams scoured through the big disaster zone overnight into Saturday.

Brazil’s new government led by President Jair Bolsonaro reacted to its first big emergency since taking office early this month by launching disaster coordination between the defense, mining and environment ministries and authorities in the affected state of Minas Gerais.

Bolsonaro and his defense minister were to fly over the zone on Saturday. His environment minister raced to the area late Friday.

An AFP photographer viewing the zone from the air described tractors, houses and a bridge submerged in mud, and emergency crews using earth-moving machinery to search for survivors.

Television images earlier showed helicopters being used to rescue people stuck in mud. – ‘Human tragedy’ –Schvartsman called the dam break “a human tragedy, because we’re talking about probably a large number of victims — we don’t know how many but we know it will be a high number.”

He said more than 100 of the mine’s employees had been located alive, but the rest were missing.

Schvartsman, who had his two-year term renewed just last month by Vale’s board, said the it had been an “inactive dam” that was in the process of being decommissioned that burst apart.