Brazil's President Jair Bolsonaro is due to undergo surgery to correct an incisional hernia, his fourth operation since he was stabbed nearly a year ago during the presidential campaign

Brazil's President Jair Bolsonaro will skip a regional summit on fires that have devastated swaths of the Amazon because doctors want him to get ready for surgery scheduled for next week, a spokesman said Monday.

The far-right president has been widely criticized over his support for Amazon deforestation and a delayed reaction to wildfires that have hit the rain forest.

Bolsonaro has to go on a liquid diet starting Friday, the same day as the summit in Colombia, and this makes the trip unfeasible, said spokesman Otavio Rego Barros.

Brazil is considering sending a substitute or even asking that the meeting be postponed, said the spokesman.

Bolsonaro is due to undergo surgery Sunday to correct an incisional hernia, his fourth operation since he was stabbed nearly a year ago during the presidential campaign.

Doctors said Bolsonaro would need 10 days' rest following the operation, which would be performed in Sao Paulo.

Earlier Monday, the president vowed to defend his controversial Amazon policy at this month's UN General Assembly even if he had to do so "in a wheelchair."

"I will appear before the UN even in a wheelchair, on a stretcher. I will appear because I want to talk about the Amazon," Bolsonaro told reporters outside his official residence in Brasilia.

Brazil traditionally makes the first speech at the General Assembly meeting, set for September 24.

Responding to criticism of his policy, Bolsonaro has accused France and Germany of attempting to buy Brazil's sovereignty after the G7 group of rich democracies offered $20 million in Amazon fire aid.

Brazil's President Jair Bolsonaro is due to undergo surgery to correct an incisional hernia, his fourth operation since he was stabbed nearly a year ago during the presidential campaign