At least 17 people have been killed and more than 50 injured after a tailings dam burst at Samarco's Germano mining site near the town of Mariana in Minas Gerais, south-east Brazil.
Located close to the Gualaxo do Norte river, the Fundao dam contained tailings, a mining waste product of metal filings, water and burst in the mining region between Ouro Preto and Mariana.
The dam released heavy water and mud into the town of Bento Rodrigues.
The burst dam devastated the nearby town with mudslides that destroyed dozens of homes.
Samarco said in a statement that the company is mobilising every effort to prioritise care for people and the mitigation of environmental damage.
The company added that it informed authorities, with response teams on-site to provide assistance.
As the dam is located close to the river, potential water contamination is also expected.
Samarco is a joint venture between iron ore firms Vale in Brazil and Australia-based BHP Billiton, producing around 30 million tonnes of iron ore annually.