“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. “We do not have the resources for that.”
Fires in the Amazon have surged 83% so far this year compared to the same period a year earlier, government figures show, destroying vast swathes of a forest considered a vital bulwark against climate change.
Although fires are a regular and natural occurrence during the regular dry season at this time of year, environmentalists blamed the sharp rise on farmers setting the forest alight to clear land for pasture.
On Wednesday, Bolsonaro said, without supporting evidence, that non-governmental organizations were behind the fires.
Questioned again on Thursday about those comments, he said he could not prove that NGOs, for whom he has cut funding, were lighting the fires but that they were “the most likely suspects.”
The firebrand right-wing president has repeatedly said he believes Brazil should open the Amazon up to business interests, to allow mining and logging companies to exploit its natural resources.
“As NGOs lose funding ... What can they do?,” he asked. “Try to take me down, try to take me down. That’s all that’s left for them to do.”
Brazil is facing growing international criticism over its handling of the Amazon, 60% of which lies in the country.
Earlier this month, Norway and Germany suspended funding for projects to curb deforestation in Brazil after becoming alarmed by changes to the way projects were selected under Bolsonaro.
At the time, when asked about the loss of German funding, Bolsonaro said “Brazil does not need that.”
Other officials have expressed concern over the fires.
Brazil’s lower house speaker, Rodrigo Maia, said on Twitter he would create “an external committee” to monitor the burning of the rainforest. He also vowed to form a group “to evaluate the situation and propose solutions to the government.”
The Bishops Conference for Latin America expressed concern about what it called “a tragedy,” and on Thursday called on countries to take immediate action to protect the rainforest and the communities that live in and around it.
“We urge the governments of the Amazon countries, especially Brazil and Bolivia, the United Nations and the international community to take serious measures to save the world’s lungs,” the Bishops Conference said.
“If the Amazon suffers, the world suffers,” the statement said.