French President Emmanuel Macron has said the record number of fires in the Amazon rainforest is an "international crisis" that needs to be on the top of the agenda at the G7 summit.
"Our house is burning," Mr Macron tweeted.
Brazil's President Jair Bolsonaro responded by accusing Mr Macron of using the issue for "political gain".
He said calls to discuss the fires at the G7 summit, which Brazil is not participating in, evoke "a misplaced colonialist mindset".
Smoke rises from the forest in a region of the Amazon near the Colombian border. Photo: AFP / Chico Batata / dpa
Satellite data published by the National Institute for Space Research (Inpe) has shown an increase of 85 percent this year in fires across Brazil, most of them in the Amazon region.
Conservationists have blamed Mr Bolsonaro's government for the Amazon's plight, saying that he has encouraged loggers and farmers to clear the land.
Mr Bolsonaro has suggested that non-governmental organisations started the fires, but admitted he had no evidence for this claim. In comments on Thursday, he acknowledged that farmers might be involved in setting fires in the region, according to Reuters news agency.
The largest rainforest in the world, the Amazon is a vital carbon store that slows down the pace of global warming.
Leaders' positions
Mr Macron, host of this weekend's G7 summit of some of the world's most advanced economies, warned that the health of the Amazon was a matter of international concern.
"The Amazon rainforest - the lungs which produce 20 percent of our planet's oxygen - is on fire," he tweeted. "Members of the G7 Summit, let's discuss this emergency first order in two days!"
Mr Bolsonaro responded by accusing the French president of using a Brazilian domestic issue for "personal political gain".
He said he was open to dialogue about the fires if it was "based on objective data and mutual respect", but hit out at the calls for it to be discussed at the G7 summit.
"The French president's suggestion that Amazonian issues be discussed at the G7 without the participation of the countries of the region evokes a misplaced colonialist mindset, which does not belong in the 21st century," he wrote on social media.
UN Secretary-General Antonio Guterres has also said he is "deeply concerned" about the fires in the Amazon.
"In the midst of the global climate crisis, we cannot afford more damage to a major source of oxygen and biodiversity. The Amazon must be protected," he tweeted.
Bolsonaro reaction
Brazilian President Jair Bolsonaro Photo: Mateus Bonomi / AGIF via AFP
Mr Bolsonaro has said that the country is not equipped to fight the fires. "The Amazon is bigger than Europe, how will you fight criminal fires in such an area?," he asked reporters as he left the presidential residence on Thursday. "We do not have the resources for that."
The president has suggested that NGOs may have started fires as revenge for his government slashing their funding.
Asked on Thursday who was responsible, he said: "The Indians, do you want me to blame the Indians? Do you want me to blame the Martians?... Everyone is a suspect, but the biggest suspects are NGOs."
When asked if there was any proof of this, he replied: "Did I accuse NGOs directly? I just said I suspect them."
Mr Bolsonaro has further angered those concerned over the spike in fires by brushing off the latest data.
He argued that it was the season of the "queimada", when farmers burn land to clear it before planting. However, Inpe has noted that the number of fires is not in line with those normally reported during the dry season.
It is not the first time that Mr Bolsonaro has cast doubt on figures suggesting that the Amazon is deteriorating rapidly.
Last month, he accused Inpe's director of lying about the scale of deforestation there. It came after Inpe published data showing an 88% increase in deforestation in the Amazon in June compared to the same month a year ago.
The director of the agency later announced that he was being sacked amid the row.
Development over environment
Climate activists and conservationists have been scathing about the Bolsonaro government and its policies, which favour development over conservation.
They say that since President Bolsonaro took office, the Amazon rainforest has suffered losses at an accelerated rate.
Their anger was further fuelled by satellite data showing a steep rise in fires in the Amazon region this year.
The figures suggest there have been more than 75,000 fires so far this year for the whole of Brazil, compared with just over 40,000 over the same period in 2018.
The figures and satellite images showing most of the state of Roraima, in northern Brazil, covered by smoke have shocked many Brazilians and triggered a global Twitter trend under the hashtag #prayforamazonia.
US space agency Nasa has on the other hand said that overall fire activity in the Amazon basin is slightly below average this year.
As well as being a vital carbon store, the region is home to about three million species of plants and animals, and one million indigenous people.
Cause of blazes
Wildfires often in the dry season in Brazil, but they are also deliberately started in efforts to illegally deforest land for cattle ranching.
"The dry season creates the favourable conditions for the use and spread of fire, but starting a fire is the work of humans, either deliberately or by accident," Inpe researcher Alberto Setzer told Reuters news agency.
Ricardo Mello, head of the World Wide Fund for Nature (WWF) Amazon Programme, said the fires were "a consequence of the increase in deforestation seen in recent figures".
- BBC