BUENOS AIRES, Argentina – Wind-blown fires scorching the parched Paraguayan countryside have scarred almost 3 million acres of forest, brush, pasture and farmland, officials said Friday, forcing the evacuation of 15,000 people and threatening nature reserves.

A drought and the common practice of burning land for agriculture have contributed to the disaster, which some authorities have called the worst fires in Paraguay’s history.

“The complexity of the situation is well beyond human control,” Jose Key Kanasawa, chief of the National Emergency Service, told Inter-Press Service. “The only thing we can do is contain it, resist it, stop it from spreading and pray that the rain comes.”

Authorities have blamed an explosion of separate blazes largely on peasants who routinely use fires to clear pasture and farmland, especially to plant export crops such as soy beans and cotton. Hot, dry and windy weather have fanned the blazes.

But experts cite other culprits: illegal loggers seeking access to protected forest areas, illicit hunters opening paths and clandestine marijuana farmers. Many of the affected regions have few police officers or authorities.

“These fires are all set in an illegal fashion,” said Maria del Carmen Fleytas, Paraguay coordinator for the Moises Bertoni Foundation, an environmental group. “Then they lose control and the fires spread. It’s hard for the state to stop this in vast sections of the country.”

Several fires are nearing the sprawling Mbaracayu Natural Reserve, home to numerous threatened mammal, bird and plant species, the foundation said.

Hundreds of raging fires have struck the landlocked South American nation in recent weeks, mostly in sparsely populated regions to the north and east of the capital, Asuncion. Thick smoke has caused some flights to be diverted from the capital.

Officials declared a national emergency in four provinces this week amid fierce criticism that the government of President Nicanor Duarte Frutos had failed to recognize the severity of the threat. The current scenario is grave, the president acknowledged.

“The reaction of the government has been very slow,” said Fleytas. “Now it’s very late, and much of the eastern region is burning.”

The specter of smoke and flames have prompted considerable national reflection about the practice of using fire as a land-clearance strategy, a widespread custom in South America.

“Paraguay is dry and in flames,” columnist Andres Colman Gutierrez wrote on the W eb site of the newspaper Ultima Hora. “We Paraguayans were born in a land that appears to be a paradise, but we do everything possible to make it into a hell.”

Meteorologists have predicted no letup in dry and windy conditions.

Authorities in neighboring Brazil have contributed four water-tanker aircraft in a bid to douse the blazes, officials said. The Paraguayan government also was seeking to rent a Russian air-tanker capable of dropping more than 10,000 gallons of water per flight, but the craft was called to firefighting duties in Russia.

The media have reported only one fatality: Wilder Smith, 40, a farmer, died when a tree fell on him as he was trying to put out a fire in his land some 100 miles east of Asuncion.