RIO DE JANEIRO (AP) — Firefighters on Monday battled flames spreading through a national park in Brazil that is enveloping Brasilia in smoke. It's the latest wildfire in the country, which is experiencing an historic drought.

More than 90 firefighters were trying to extinguish blazes that have already burned through 700 hectares (1,700 acres) of the conservation area of Brasilia National Park. Two aircraft from the Federal District’s military firefighting unit and another two from the nearby Chapada dos Veadeiros national park are being mobilized, according to a statement from ICMBio, the government agency that manages the park.

The head of the agency, Mauro Pires, told newspaper Folha de S.Paulo that the fire was human-caused and appears to have started near the edge of a farm.

Smoke from the fire smothered the capital, Brasilia, on Monday, and columns of black smoke were visible from several points in the city.

Brazil has been enveloped in smoke in recent weeks, as fires rage in the Amazon rainforest, the Cerrado savanna and the Pantanal wetlands. Those uncontrolled, human-made wildfires have ravaged protected areas and spread smoke over a vast expanse, causing air quality to plummet.

The country is also enduring its worst drought since nationwide measurements began more than seven decades ago, with 59% of the country affected — an area roughly half the size of the U.S. Major Amazon basin rivers are registering historic lows.

A task force of the Federal District’s public security agency is working with the Federal Police to investigate possible criminal actions in the fire in the Brasilia National Park, the agency said in a statement, adding that around 1,500 agents from the district's government are working to combat fires in the region.

President Luiz Inácio Lula da Silva said on Instagram that the Federal Police have opened 52 investigations “against those responsible for the crimes against our country,” adding that he would be meeting with Environment Minister Marina Silva to “discuss further actions to deal with this climate emergency.” On Sunday, he did a flyover of the park that's spread across three of the Federal District's administrative regions, including Brasilia, and one municipality in Goias state.

Supreme Court Justice Flávio Dino issued a ruling on Sunday authorizing the federal government to direct extra funds toward combating forest fires and hiring firefighters.

Scientists say that climate change — primarily caused by the burning of fossil fuels such as oil, gas and coal — makes extreme weather more likely, favoring conditions for events such as wildfires and floods.