A massive fire, 50 kilometers long (31 miles), is advancing towards the Pantanal valley in Brazil.
The governor's office in Mato Grosso do Sul state said the fire "is the largest ever seen" in the region.
So far at least 50,000 hectares of vegetation have been destroyed.
This area, which is located in the southern part of the country, is one of the most biodiverse regions in the world and a very popular tourist destination.
The fire started on October 25 and is said to be spreading rapidly, due to a combination of high temperatures and strong winds.
The governor's office said in a statement that the situation was "critical." It also warned that visibility in the area is poor.
The governor has declared a 30-day moratorium on the use of fire to clear land.
Firefighters are also using airplanes to try to extinguish the fire from above.
As of October 30, more than 8,000 fires have been recorded in the Pantanal, an increase of 462% over the same period last year.
Brazil has been hit by a significant number of wildfires this year. Official figures show that more than 167,000 forest fires were recorded from January to October 30 of this year.
