Hundreds of new fires have flared up in the Amazon in Brazil as military aircraft dumped water over hard-hit areas and G7 nations pledged to help.
Smoke choked Port Velho city as fires raged in the north-western state of Rondonia where firefighting efforts are concentrated, amid a growing global uproar and a diplomatic spat between France and Brazil.
Two C-130 Hercules aircraft dumped water on Sunday on fires devouring parts of the world's largest rainforest, which is considered crucial to keep climate change in check.
Large areas of the remote region have been scorched by the worst fires in years.
Experts say increased land clearing during the months-long dry season to make way for crops or grazing has aggravated the problem.
The worsening crisis has fuelled a row between Brazilian President Jair Bolsonaro and French leader Emmanuel Macron, who has been pushing for more action to protect the forest.
Mr Macron on Monday condemned Mr Bolsonaro's "extraordinarily rude" comments about his wife Brigitte.
The Brazilian leader hit back, accusing the French president of treating Brazil like "a colony or no-man's land".
G7 nations meeting in south-western France agreed to spend $20 million (Dh73.4m) on the Amazon, mainly by send firefighting aircraft.
The G7 also agreed to support a medium-term reforestation plan to be unveiled at the UN in September, said Mr Macron and Chile's President, Sebastian Pinera.
Although about 60 per cent of the Amazon is in Brazil, the vast forest also spreads over parts of eight other countries or territories.
Bolivian President Evo Morales said on Sunday that he would accept international help to battle fires raging in his country's south-east as he suspended his election campaign to deal with the crisis.
Bolivia took delivery on Friday of a Boeing 747-400 supertanker, capable of carrying 150,000 litres of water.
Brazil has accepted an offer from Israel to send an aircraft.
Seven states, including Rondonia, have requested the Brazilian army's help in the Amazon, where more than 43,000 troops have been made available to battle blazes.
After initially blaming the fires on non-government organisations, Mr Bolsonaro on Friday pledged a zero-tolerance approach to crimes in the Amazon and promised strong action to control the blaze.
Dozens of firefighters arrived in Porto Velho on Sunday and Justice Minister Sergio Moro has given the green light for security forces to tackle illegal deforestation.
The latest official figures show 80,626 forest fires have been recorded in Brazil this year, the highest number of any year since at least 2013.
More than half of the fires are in the enormous Amazon basin.
Between Saturday and Sunday, 1,113 new fires were ignited, Brazil's National Institute for Space Research said.