Homes and vehicles were engulfed in thick, red mud Thursday after a dam burst at an iron ore mine in southeastern Brazil.
Aerial pictures showed several hundred meters of industrial sludge overrunning the small town of Bento Rodrigues, about seven kilometers below the Fundao Dam in the state of Minas Gerais.
Rescue teams were on the scene, and residents were ordered to evacuate.
The dam was built to hold back water and mine tailings, a mixture that often can be toxic.
Authorities said there were fatalities and that some people were missing, but they gave no figures. Reuters quoted Globo Media as reporting that at least 15 people were dead and 45 others were missing.
Brazilian mining company Samarco, which owns the mine, said on its website that it could not yet say what caused the dam to burst or what the extent of the disaster was.
Samarco is jointly owned by mining giants Vale of Brazil and BHP Billiton of Australia.