(This Aug. 26 story has been corrected to fix the location of fires to Sao Paulo, not north of Brazil, in paragraph 1)
BRASILIA (Reuters) - Four men have been arrested on suspicion of setting fires that have destroyed thousands of hectares of sugarcane plantations in the north of the Brazilian state of Sao Paulo, the government said on Monday.
The fires spread rapidly into the weekend through parched fields at the peak of the country's dry season in a region that has not had rain for months. Clouds of smoke cloaked nearby cities where outdoor activities were restricted, and highways and airport operations disrupted due to low visibility.
"We had an explosive combination of three factors: high temperature, very strong winds and very low relative humidity in the last few days. So, anything could cause an ignition," Sao Paulo Governor Tarcisio de Freitas said at a press conference.
He said three suspects were arrested in the region with containers of gasoline to start fires and a fourth man was arrested on Monday when he was caught setting fire to grass. Federal police are investigating the fires for suspected arson.
Dry weather has increased the frequency of wildfires across Brazil this year, including in the Amazon (NASDAQ:AMZN) region. Environmental experts said higher temperatures brought by climate change and widespread deforestation have contributed to the doubling of the number of fires this season.
In the Xingu Park, Chief Megaron Txucarramae called for help to control a fire raging in Brazil's most famous Indigenous reservation. "Help! Send firefighters and planes that throw water," he pleaded on television.
Sao Paulo's governor said there were no new fires burning in the sugarcane fields but dozens of towns were still on high alert for more blazes. In Ribeirao Preto, a city in the most affected region in the west of Sao Paulo state, school classes were canceled on Monday due to the smoke-filled atmosphere.
Freitas estimated the damage to farm crops from the fires at more than 1 billion reais ($182 million).
Sao Paulo is the largest sugar-producing state in Brazil, the world's top producer and exporter of the sweetener.
Brazil's largest sugar group Raizen SA said it resumed operations at its Santa Elisa mill on Sunday. The plant had to be evacuated on Thursday due to the proximity of fires.
($1 = 5.4968 reais)