BRASILIA (REUTERS) - European leaders on Friday (Aug 23) threatened to tear up a trade deal with South America, reflecting the growing international dismay and anger with Brazil as a record number of fires in the Amazon rainforest intensified the unfolding environmental crisis.

Against the global chorus of condemnation, Brazilian President Jair Bolsonaro was mobilising the army to help combat the blazes, while his administration launched a diplomatic charm offensive to try to mend bridges.

The Trump administration said it was "deeply concerned"about the wildfires, which now look set to be discussed at a summit of Group of 7 (G-7) leaders in France this weekend.

French President Emmanuel Macron's office went so far as to accuse Bolsonaro of lying when he downplayed concerns over climate change at the G-20 summit in June.

France and Ireland said on Friday they would now oppose the EU-Mercosur farming deal struck in June between the European Union and the Mercosur countries of Brazil, Argentina, Uruguay and Paraguay.

"There is no way that Ireland will vote for the EU-Mercosur Free Trade Agreement if Brazil does not honor its environmental commitments," Ireland's Prime Minister Leo Varadkar said in a statement.

The EU-Mercosur deal took 20 years to negotiate, but will not be officially ratified for another two years.

Brazilian Business leaders also warned the backlash over Brazil's environmental record could sink its efforts to join the Organisation for Economic Cooperation and Development (OECD), a Paris-based club of 37 developed nations whose imprimatur is required by many institutional investors.

Stung by the international outcry, Bolsonaro signed off on sending in the Brazilian army to fight fires, Antonio Denarium, governor of the Amazon state of Roraima, said on Friday.

Brazil also distributed a 12-page circular, exclusively seen by Reuters, to foreign embassies, outlining data and statistics defending the government's reputation on the environment.

Having first dismissed the fires as natural, then blaming non-governmental organisations without evidence for lighting them, Bolsonaro struck a more serious note on Friday, saying he would summon top Cabinet members to tailor a response.

Asked by reporters in Brasilia if he would send in the army, he said: "That is the expectation."

Bolsonaro met with a team of senior officials on Friday afternoon, including the defence and environment ministers as well as the foreign minister, to hammer out a response to the crisis. He was due to address the nation at 8.30pm (7.30am in Saturday, Singapore time) to discuss the measures.

Agriculture Minister Tereza Cristina Dias insisted that Brazil was "taking care" of the Amazon, and that international concerns over the fires should be cooled down.

"The news is worrying, but I think we have to lower the temperature. The Amazon is important, Brazil knows that, and Brazil is taking care of the Amazon," Dias told reporters.

'HEARTBREAKING'

Forest fires in the Brazilian Amazon, which accounts for more than half of the world's largest rainforest, have surged 83 per cent in number this year, according to government data, destroying vast swathes of a vital bulwark against global climate change.

The government agency INPE has registered 72,843 fires, the highest number since records began in 2013. More than 9,500 have been spotted by satellites over the past week.

Although fires are a regular and natural occurrence during the dry season at this time of year, environmentalists blamed the jump on farmers clearing land for pasture.

Farmers may have had at least tacit encouragement from the firebrand right-wing president, who took power in January.

Bolsonaro has repeatedly said he believes Brazil should open up the Amazon to business interests, allowing mining, agricultural and logging companies to exploit its natural resources.

On Thursday, Bolsonaro admitted for the first time that farmers may be behind some of the fires.

As the fires burned, foreign pressure continued to grow.

Several hundred activists protested outside the Brazilian embassies in Paris and London on Friday.

British Prime Minister Boris Johnson tweeted that the fires were "not only heartbreaking, they are an international crisis,"while a spokeswoman said Johnson would use the summit of G-7 leaders this weekend to call for a renewed focus on protecting nature.

German Chancellor Angela Merkel and France's Macron also called for the fires to be on the G-7 agenda.

Alexandre Antonelli, director of science at Britain's Kew Royal Botanic Gardens, urged that import sanctions be imposed on Brazil because of the fires.

"Immediate action is necessary to extinguish the current fires and prevent future ones," the Brazilian scientist said.

On Thursday, Bolsonaro responded angrily to what he saw as foreign interference.

"These countries that send money here, they don't send it out of charity... They send it with the aim of interfering with our sovereignty," he said.