Witnesses report the town of Bento Rodrigues, near Mariana, Brazil, has completely flooded

A dam in the south-eastern Brazilian town of Mariana in the state of Minas Gerais has broken, killing at least 16, according to local media.

Witnesses report the town of Bento Rodrigues, near Mariana, has been completely flooded; the town has a population of 620

There was no official word on any victims by early evening (local time). Rescue teams were searching for survivors or bodies, and residents living nearby were told to evacuate to higher ground.

TWITTER An image reportedly from the scene.

Images from Globo TV showed the strip-mining operation overrun with water and mud, and large vehicles tossed on their sides.

Authorities said the dam was built to hold back water and residue from mining operations, a mixture that can often be toxic.

The Samarco mining company said in a statement on its website that it was making "every effort to prioritize care to people and mitigate damage to the environment".

TWITTER/G1 This town is devastated by the flood.

"It is not possible at this moment to confirm a cause ... nor if there are victims," it added.

Police, firefighters and city officials also said they could not confirm any victims.

A statement from the city hall of Mariana, a city of about 40,000 people 300 kilometres north of Rio de Janeiro, said the dam ruptured at 4:20 pm in an area roughly 20 kms from the city centre.