A girl attends a protest called by intellectuals and artists against the destruction of the Amazon rainforest, at Ipanema Beach in Rio de Janeiro, Brazil, on Sunday. Brazil on Sunday deployed two warplanes to douse fires devouring parts of the Amazon rainforest, as hundreds of new blazes were ignited ahead of nationwide protests over the destruction. Photo: AFP

Brazilian warplanes were dumping water on the burning forest in the Amazon state of Rondonia, responding to a global outcry over the destruction of the world's largest tropical rainforest.

As of Sunday, President Jair Bolsonaro had authorized military operations in seven states to combat raging fires in the Amazon, responding to requests for assistance from their local governments, a spokeswoman for his office said.

Reuters accompanied a firefighting brigade near the state capital of Porto Velho, where there were areas larger than soccer fields that had been charred, but active fires were contained to small areas of individual trees.

The dozen or so yellow clad firefighters from environmental enforcement agency Ibama easily cleared brush from around a burning stump with a leaf blower, doused it with jets connected to water packs mounted on their backs and covered it in earth.

A video posted by the Defense Ministry on Saturday evening showed a military plane pumping thousands of liters  of water out of two giant jets as it passed through clouds of smoke close to the forest canopy.

The response comes as leaders of countries in the Group of Seven (G7) nations currently meeting in France expressed grave concerns over the fires.

French President Emmanuel Macron on Sunday said the G7 was nearing a deal to provide "technical and financial help" to countries affected by the Amazon fires.

Nearly 80,000 fires have been registered across Brazil through August 24, the highest since at least 2013, according to space research agency INPE.

Bolsonaro announced the military would be sent in on Friday after several days of criticism from the public and world leaders that Brazil's government was not doing anything to fight the fires.

He also said on Twitter he had accepted Israeli Prime Minister Benjamin Netanyahu's offer of a plane and specialized support for the firefighting operations, following a call between the two leaders.

But outside of Rondonia, the government had yet to provide any operational details for other states. 

The Defense Ministry said in a briefing on Saturday that 44,000 troops were available in Brazil's northern Amazon region but did not say how many would be used where and what they would do.