Four people were wounded Wednesday in a gunfight between Brazilian federal police and Munduruku Indians in a remote Amazonian village, authorities said.
The clash took place in a hamlet outside the town of Alta Floresta, 775 kilometers (481 miles) north of Cuiaba, capital of Mato Grosso state.
The police involved in the incident were part of a multistate operation targeting illegal gold mining.
The officers came under attack with bullets and arrows as they were destroying equipment allegedly used in illegal mining, a police spokesman told Efe.
Two Munduruku and two cops were hurt in the ensuing battle.
One of the Indians was airlifted to a hospital in Cuiaba, while the other Munduruku and the two wounded officers were treated in Alta Floresta, the spokesman said.
Operation Eldorado began Tuesday, when 300 police officers deployed across seven states to execute dozens of arrest- and search-warrants after a 10-month investigation of three companies that buy gold from wildcat miners and then resell it to unwitting investors in Sao Paulo, Brazil's largest city and business capital.
The illegal mining has generated more than 150 million reais ($73 million) for the firms involved, police said. EFE