(Adds Vale shares fall, previous dam burst in 2015, details) A...

(Adds Vale shares fall, previous dam burst in 2015, details)

A tailings dam burst at an iron ore mine owned by Brazilian miner Vale SA VALE3.SA on Friday, releasing a river of sludge that covered nearby buildings and forced the evacuation of some residents from the affected region in southwestern Minas Gerais state.

Vale and local authorities said leaked tailings from the Corrego de Feijao mine had spread into the mine's administrative area and to parts of the local community Vila Forteco, near the town of Brumadinho.

There were no confirmed reports of fatalities or injuries in the area, the authorities said.

The accident comes three years after Brazil's worst environmental disaster when a larger dam owned jointly by Vale and BHP Billiton (BHP) broke in the same region, burying local homes and killing 19 people.

Friday's incident appeared to pale in comparison with the 2015 disaster in Mariana in Minas Gerais, when the tailings dam at the Samarco iron ore mine burst.

Operations at Samarco remain halted over legal disputes relating to damages the rupture caused even after the companies settled a $5.28 billion civil lawsuit last year.

U.S.-listed shares of Vale fell 8 percent in early afternoon trading.

Photos on G1 and other local news websites, some credited to the fire department, showed a vast area covered in sludge with people walking in ankle deep mud. Images showed firemen rescuing at least three people from the mud.

A representative of the civil defense agency in the nearby town of Brumadinho located about six miles (10 km) from the dam said they were evacuating homes in the lower district by the river, but the mud had not arrived there.

The Inhotim Institute, an outdoor contemporary art museum in a park three miles from Brumadinho, evacuated visitors and closed its doors out of safety precautions.