Brazilian environmental authorities have declared a "red alert" as fires raged toward one of the country's biggest and best preserved Indian reservations. Flames were devouring farmland in central Mato Grosso sate and heading for the Xingu National Park, where 17 different indegenous groups live in a densely forested area bigger than Belgium and prized by scientists for its rich biodiversity.A spokesman for the government's National Indian Foundation said the flames were just 4 kilometers (2.5 miles) from the park's perimeter.