Video report by ITV News Correspondent Juliet Bremner
French President Emmanuel Macron has accused his Brazilian counterpart Jair Bolsonaro of lying and has threatened to block an European Union trade deal with the South American country as tensions grow over the response to the wildfires in the Amazon.
Mr Macron's stance is an escalation of the war of words between Brasilia and Paris over the record numbers of wildfires sweeping through the Amazon rainforest.
In a strongly worded statement from the Elysee Palace, Marcon said that "in light of Brazil's attitude these recent weeks", he could "only conclude that President Bolsonaro lied to him during the Osaka Summit" in June where climate change was among topics discussed.
Mr Macron said: "The decisions and statements from Brazil these recent weeks show clearly that President Bolsonaro has decided to not respect his commitments on the climate, nor to involve himself on the issue of biodiversity."
As a consequence, France now opposes an EU trade deal - 20 years in the brokering - "in its current state" with the Mercosur bloc of South American nations that includes Brazil, Argentina, Paraguay and Uruguay.
His words appeared to spark a response, however, as President Bolsonaro later indicated the army would be sent in to fight the fires.
Irish Taoiseach Leo Varadkar echoed Mr Macron's message, warning Ireland will not back the controversial EU-Mercosur deal unless Brazil's government protects its rainforest.
He accused Bolsonaro's attempts to blame the fires on environmental NGOs (non-governmental organisations) as "Orwellian".
In a statement, he said: "The Mercosur deal is two years away from a vote on approval in Europe. During the course of these two years, we will monitor closely Brazil's environmental actions.
"There is no way we can tell Irish and European farmers to use fewer pesticides, less fertiliser, embrace biodiversity and plant more of their land, and expect them to do it, if we do not make trade deals contingent on decent environmental, labour and product standards.
"The political agreement on Mercosur does that. We'll monitor closely if they mean it."
The EU-Mercosur trade agreement was drawn up in June 2019 after 20 years of negotiations, but has not get been ratified.
Mr Macron put the wildfires on the international stage on Thursday, calling it a global crisis. He said the leaders of the G7 nations should hold urgent discussions about them at their summit in France this weekend.
"Our house is burning. Literally. The Amazon rain forest - the lungs which produces 20% of our planet's oxygen - is on fire," Macron tweeted.
President Bolsonaro fired back with his own tweet, saying: "I regret that Macron seeks to make personal political gains in an internal matter for Brazil and other Amazonian countries.
"The sensationalist tone he used does nothing to solve the problem."
US president Donald Trump tweeted that America was poised to help out in any way it could - his first reference to the fires.
Onyx Lorenzoni, the president's chief of staff, earlier in the day accused European countries of exaggerating environmental problems in Brazil in order to disrupt its commercial interests.
"There is deforestation in Brazil, yes, but not at the rate and level that they say," said Lorenzoni, according to the Brazilian news website globo.com.
His allegation came after Germany and Norway, citing Brazil's apparent lack of commitment to fighting deforestation, decided to withhold more than £70 million in funds earmarked for sustainability projects in Brazilian forests.
A Downing Street spokesperson said: “The Prime Minister is deeply concerned by the increase in fires in the Amazon rainforest and the impact of the tragic loss of these precious habitats.
“The effect of these fires will be felt around the world which is why we need international action to protect the world’s rainforests.
“The UK will continue to support projects in Brazil to do this, and the Prime Minister will use the G7 to call for a renewed focus on protecting nature and tackling climate change together.”
Will the Amazon wildfires be a topic of discussion for President Donald Trump at the G7 Summit?
The European Commission added it was "deeply worried" about the situation and welcomed the French President's intention to discuss the fires at the G7 meeting summit.
The commission's chief spokeswoman, Mina Andreeva, said "the sense of urgency is indeed warranted".
"We are in touch, as always, with the Brazilian and Bolivian authorities and stand ready to assist in anyway we can, for instance by providing assistance or activating our Copernicus satellite mapping system," she said.
On Thursday, the right-wing nationalist Bolsonaro, who only came into power at the start of the year, repeated the blame for the fires lies with environmental groups who are trying to make him look bad.
"I strongly suspect it's the environmental groups," he said.
When asked by a reporter what proof he had, he said: "For God's sake there is no proof, nobody admits 'I set fire to that'."
But even in his own country, there are many that don't believe him.
At a climate change conference in the north of Brazil, when the environment minister approached the stage to speak, he was heckled and drowned out by protesters.
The WWF conservation group also challenged Bolsonaro's allegations about NGOs, saying they divert "the focus of attention from what really matters: the well-being of nature and the people of the Amazon."
In London, there were protests by environmental group Extinction Rebellion outside the Brazilian embassy on Friday.
Brazil contains about 60 percent of the Amazon rainforest, whose degradation could have severe consequences for global climate and rainfall.
The Amazon rainforest covers 5.5million square kilometers - more than 23 times the size of the UK.
It absorbs a quarter of global carbon dioxide emissions and releases a fifth of our oxygen.
But deforestation is surging - last month alone more than 2,000 square kilometres was lost.
Mr Bolsanaro's policy of encouraging farmers to plant more crops and keep more cattle rather than protecting the forest is widely criticised as why deforestation is accelerating.
It is thought that the fires may be being started to clear rainforest so that crops and livestock can be farmed on it instead.
Richard George, from Greenpeace UK said large international companies can't afford to do business with a country that is "putting the Amazon to the torch."
He's playing to a very small home crowd but he's picking fights and this is a fight that he can't afford to win.
"Most of the international community is horrified by this and big companies like McDonald's and KFC, who buy commodities from Brazil, really have a choice, you know, they can't continue doing business with a country that is putting the Amazon to the torch."