BRASILIA - Three men have been arrested on suspicion of setting fires that have destroyed thousands of hectares of sugarcane plantations in northern Sao Paulo state, its Governor Tarcisio de Freitas said on Monday.

The fires spread rapidly into the weekend through parched fields at the peak of Brazil'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," Freitas said at a press conference.

He said three men were arrested in the region and suspected of starting the fires. Local media said they were caught with containers of gasoline.

In Ribeirao Preto, a city in the most affected region in the west of Sao Paulo state, school classes were canceled on Monday.

The governor said there were no new fires burning in the sugarcane fields but dozens of towns were still on high alert for more blazes.

Freitas estimated the damage to farm crops from the fires at more than 1 billion reais ($182 million).

São 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.

  - Reuters