(Photo: Xinhua)

At least nine people were killed and nearly 300 others went missing after a tailings dam owned by mining giant Vale collapsed Friday afternoon in Brazil's southeastern state of Minas Gerais, according to the state government.

The identities of the victims were not disclosed. Some 100 people who were isolated were also rescued, local authorities said.

The dam collapsed Friday afternoon in Brumadinho Municipality and caused a mudslide, which destroyed Vale's offices and a residential area.

Some 100 firefighters and civil rescuers are working at the site. Another 200 are expected to reach the Brumadinho region in the early hours of Saturday.

At a press conference on Friday evening, Vale CEO Fabio Schvartsman said that the number of victims from the dam collapse was "terrible." He said he was "shaken" by the incident and committed to taking all necessary measures to find out what happened.

According to him, the dam was inactive and all reports attested that it was safe.

"It is important that we state that this is an inactive dam. It was not operational for over three years and was in the process of being decommissioned," he said.

A second dam overflowed but did not burst, Vale said. Hours later, the mudslide reached the nearby Paraopeba River.

State authorities decided to suspend the collection of water from the Paraopeba River as a precaution, though Vale said there is a minimum chance of contamination.