President Jair Bolsonaro has insisted that the Brazilian areas of the Amazon rainforest are sovereign territory.
Conservationists blame Mr Bolsonaro and his government for turning a blind eye to farmers and loggers clearing land in the Amazon, hastening deforestation.
But in an address at the United Nations in New York, he struck a defiant note.
He said it was a “fallacy” to describe the Amazon as the heritage of humanity and a “misconception” that its forests were the lungs of the world.
Speaking at the UN General Assembly, Mr Bolsonaro criticised what he described as sensational reporting in the international media.
“Using and resorting to these fallacies, certain countries, instead of helping … behaved in a disrespectful manner and with a colonialist spirit,” he said.
“They even called into question that which we hold as a most sacred value, our sovereignty.”
He defended his government’s treatment of indigenous people, saying many backed his policies.
“Some people both inside and outside Brazil… have insisted on treating and keeping our Indians as though they were real cave men,” he said.
The view from the ‘epicentre of the crisis’
By Will Grant, BBC Latin America correspondent, Pará state
The state of Pará is often considered the epicentre of the environmental crisis in the Amazon. From above, the range of different pressures and stresses being put onto the rainforest by human activity is abundantly clear.
As our light aircraft swooped down, the scar of open land interrupting the forest canopy revealed itself to be a vast series of illegal gold mines. The runoff and slurry were so extensive that they resembled a river – but a toxic one contaminated by mercury, which seeps into the Amazon’s waterways and ecosystems.
It is not just mining, either. In the part of the Amazon we visited, a recent wildfire had consumed an area of forest the size of 1,600 football pitches in just four days.
In the Amazonian town of Alter do Chão, opinion was split between those urging greater protection for the forest and those saying further development was needed to bring in jobs.
Yet everyone I spoke to agreed that the Amazon rainforest was a living, breathing resource that must be respected – and that fire, mining and large-scale agriculture were doing nothing but harm.
More than 80,000 fires have broken out in the Amazon rainforest so far this year.
Experts believe the majority of the fires across Brazil this year were caused by human activity such as farmers and loggers clearing land for crops or grazing.
Environmentalists say Mr Bolsonaro’s policies have led to an increase in fires this year, and that he has encouraged cattle farmers to clear large areas of the rainforest since his election last October.
Mr Bolsonaro’s visit to New York has sparked several protests.