LIMA, Peru (AP) – Indigenous protesters have occupied Peru’s biggest oilfield in the Amazon jungle near Ecuador to demand the cleanup of decades of contamination from spilled crude.

The field’s operator, PlusPetrol of Argentina, says the protest has forced it to cut back production by more than half of the 17,000 barrels of normal daily output.

The protest began Monday in the field near the Corrientes river where the government last year declared an environmental state of emergency.

Protest leader Carlos Sandi of the Shuar tribe said Thursday that the protest would continue until the government provides a solution.

He said the government has dispatched about 400 police to the region.

Pluspetrol has been operating the lot since 2001. Before that it was run by Occidental Petroleum.