The Brazilian president, Jair Bolsonaro, has accused environmental groups of setting fires in the Amazon as he tries to deflect growing international criticism of his failure to protect the world’s biggest rainforest.

A surge of fires in several Amazonian states this month followed reports that farmers were feeling emboldened to clear land for crop fields and cattle ranches because the new Brazilian government was keen to open up the region to economic activity.

Brazil has had more than 72,000 fire outbreaks so far this year, an 84% increase on the same period in 2018, according to the country’s National Institute for Space Research. More than half of them were in the Amazon.

There was a sharp spike in deforestation during July, which has been followed by extensive burning in August. Local newspapers say farmers in some regions are organising “fire days” to take advantage of weaker enforcement by the authorities.

Since Bolsonaro took power the environment agency has issued fewer penalties, and ministers have made clear that their sympathies are with loggers rather than the indigenous groups who live in the forest. The head of Brazil’s space agency was fired last month after the president disputed the official deforestation data from satellites.

An international outcry has prompted Norway and Germany to halt donations to Brazil’s Amazon fund, which supports many environmental NGOs as well as government agencies. There have also been calls for Europe to block a trade deal with Brazil and other South American nations.

Bolsonaro suggested the fires were started by environmental NGOs to embarrass his government.

“On the question of burning in the Amazon, which in my opinion may have been initiated by NGOs because they lost money, what is the intention? To bring problems to Brazil,” the president told a steel industry congress in Brasilia.

He made a similar allegation earlier in the day when he suggested groups had gone out with cameras and started fires so they could film them. Asked whether he had evidence, or whether he could name the NGOs involved, Bolsonaro said there were no written records and it was just his feeling.

Facebook Twitter Pinterest A Nasa images shows several fires burning in Brazilian states. Photograph: HO/AFP/Getty Images

Environmental activists said his comments were an absurd attempt to deflect attention from the problem of poor oversight and tacit encouragement of illegal forest clearance. “Those who destroy the Amazon and let deforestation continue unabated are encouraged by the Bolsonaro government’s actions and policies. Since taking office, the current government has been systematically dismantling Brazil’s environmental policy,” said Danicley Aguiar, of Greenpeace Brazil.

In Brazil’s Amazonas state, heat from forest fires has been above average every day this month, according to data provided to the Guardian by the Copernicus Atmosphere Monitoring Service. On the peak day, 15 August, the energy released into the atmosphere from this state was about 700% higher than the average for this date over the previous 15 years. The story was similar in Rondônia state, where there have been 10 days this month where fire heat has been more than double the average for the time of year.

Play Video 1:49 Large swathes of the Amazon rainforest are burning – video report

It is unclear which fires have been deliberately set by farmers to clear land and which were accidental or natural. The problem is not restricted to Brazil. Neighbouring Bolivia is also experiencing unusually large wildfires that have reportedly destroyed 5,180 sq km (2,000 sq miles) of forest. Video from the country’s Santa Cruz department shows monkeys and other animals scurrying in search of shelter amid a landscape reduced to blackened stumps, bare branches and ashes. Copernicus satellite images show it was primarily a fire in Bolivia that led to the darkening of the skies during the day on Monday in São Paulo, thousands of miles away.