A 60-day ban on burning in Brazil took effect Thursday after a global outcry over fires raging in the Amazon and data showing hundreds of new blazes in the rainforest.
The decree issued by President Jair Bolsonaro comes after escalating international pressure over the worst fires in the Amazon in years that have ignited a diplomatic spat between Brazil and Europe.
But activists quickly doused hopes that the ban would work.
"The people who burn without a license are not going to obey," said Rodrigo Junqueira of the Socio-Environmental Institute.
Thousands of troops and firefighters have been deployed since the weekend to combat the fires, along with two C-130 Hercules and other aircraft that are dumping water over the hardest-hit areas in the country's north.
More than 1,600 new fires were ignited between Tuesday and Wednesday, taking this year's total to almost 85,000 - the highest number since 2010, official data shows. More than half of them are in the vast Amazon basin.
The new figures comes as UN chief Antonio Guterres on Thursday mooted a meeting of key countries to drum up support to tackle the fires that have also devastated swaths of Bolivia.
"We are strongly appealing for the mobilisation of resources and we have been in contact with countries to see whether, during the high-level session of the General Assembly, there could be a meeting devoted to the mobilisation of support to the Amazon," Mr Guterres told reporters.
United Nations Secretary-General Antonio Guterres attends Lisboa+21 conference in Lisbon, Portugal. Source: United Nations
Ban 'not useful'
International offers of help for combatting the fires is a hot-button issue in Brazil, with Mr Bolsonaro and others insisting on the country's sovereign rights over the Amazon.
Mr Bolsonaro on Wednesday accused France and Germany of "buying" Brazil's sovereignty after the G7 offered $20 million in Amazon fire aid.
Vice President Hamilton Mourao - widely considered a moderate voice in Mr Bolsonaro's government - also weighed in publicly for the first time on Wednesday, insisting in an opinion piece that "our Amazon will continue to be Brazilian."
The governors of several states in the Amazon told Mr Bolsonaro in a meeting on Tuesday that international help was needed.
Their plea came after Norway and Germany halted around $70 million in Amazon protection subsidies earlier this month.
The United States is ready and willing to help Brazil fight forest fires in the Amazon, President Donald Trump said Wednesday, criticising the G7 for failing to consult Mr Bolsonaro over its initiative.
Mr Bolsonaro also renewed a demand Wednesday that French leader Emmanuel Macron withdraw "insults" against him, fueling a war of words between the two men that threatens to torpedo a huge trade deal between the European Union and South American countries, including Brazil.
In the escalating row, Mr Macron has accused Mr Bolsonaro of lying to him about Brazil's climate change stance, while Mr Bolsonaro has slammed Macron as having a colonialist mentality.
"I think Mr Bolsonaro is causing enormous harm to the Brazilian people, a little out of evil and a little out of ignorance," former president Luiz Inacio Lula da Silva told the BBC from jail where he is serving a nearly nine-year sentence for corruption.
Even as Mr Bolsonaro's decree was published Thursday, there were already doubts over how Brazil would enforce the two-month ban on burning in the remote region where deforestation has surged this year as agencies tasked with monitoring illegal activities were weakened.
"It will not be useful," a skeptical fruit shop owner in Porto Velho, the capital of the northwestern state of Rondonia, told AFP.
"There's insufficient supervision."
WWF said Brazil already had laws and tools to detect illegal deforestation and burning, but it lacked enforcement.
"The certainty of impunity is the great spark that starts the fires," WWF said.
Experts say increased land clearing during the months-long dry season to make way for crops or grazing has aggravated the recurring problem of fires.
The defense ministry says the fires are under control and that the number of blazes is falling, helped by recent rain in the affected areas.
