Two dams at an iron ore mine collapsed in Brazil on Thursday, resulting in a growing number of casualties and missing persons.

According to AFP, an official said that at least 17 people were killed.

Adao Severino Junior, fire chief of the nearby city Mariana, said there were over 50 injured victims and at least 40 missing people.

The chief added that the number of casualties was likely to rise. Mudslides have taken out roads and cell towers, complicating search and rescue efforts.

"In reality there are a lot more, but we can't confirm any more than that. We don't even know that we'll find everybody," Severino said, according to Reuters.

The disaster occurred at the small village of Bento Rodrigues, situated 4 miles beneath the burst dams. The town of 400 people was flooded with water and red toxic mud from the mining waste site. Photographs showed homes destroyed and trees leveled by the mudslides.

The local newspaper Estado de Minas shared some photos of the aftermath on Instagram:

Reuters reports Mariana Mayor Duarte Junior declared a state of emergency, with hundreds of families evacuated from the area.

Mariana is a city of about 40,000 people, 185 miles north of Rio de Janeiro. The burst dams were located about 12 miles from the city center, forcing those that lived downhill to head for higher ground.

The two dams were owned by the Samarco mining company. The reasons for the collapse have yet to be determined, but the company did say the dams had been inspected recently and cleared by environmental authorities. AFP reports Samarco has confirmed around 15 employees are missing. 

The dams were reported to be holding tailings, a mining waste product containing metal filings and sometimes chemicals.

The dams' proximity to the Gualaxo do Norte River has also raised fears of contamination. Samarco claimed that there were no chemical elements involved in the spill that could pose a health risk.

Samarco is jointly owned by Vale, the world's biggest iron-ore producer, and BHP Billiton, the world's largest mining company.

Those who have lost their homes or evacuated the areas are being housed in a gymnasium in Mariana.