Deforestation in Brazil’s portion of the Amazon rainforest rose more than 88% in June compared with the same month a year ago, the second consecutive month of rising forest destruction under the rightwing president Jair Bolsonaro.

According to data from Brazil’s space agency, deforestation in the world’s largest tropical rainforest totaled 920 sq km (355 sq miles).

The data showing the 88.4% deforestation increase is preliminary, but indicates the official annual figure, based on more detailed imaging and measured for the 12 months to the end of July, is well on track to surpass last year’s figure.

In the first 11 months, deforestation has already reached 4,565 sq km (1,762 sq miles), a 15% increase over the same period in the previous year.

Environmentalists have warned that Bolsonaro’s strong support for development in the Amazon and criticism of the country’s environmental enforcement agency for handing out too many fines would embolden loggers and ranchers seeking to profit from deforestation.

“Bolsonaro has aggravated the situation,” said Paulo Barreto, a researcher at Brazilian non-governmental organization Imazon.

The surge in deforestation comes as Brazil faces more pressure to protect its environment under the terms of the free trade deal between the European Union and South American bloc Mercosur agreed to last week.

The rainy season through April appeared to have held off a spike in deforestation that subsequently came with the dry season starting in May.

Deforestation rose 34% in May compared with the same month a year ago.

Bolsonaro’s office declined to comment, saying questions would be addressed by the environment ministry. “We are adopting all measures to combat illegal deforestation,” said the environment minister, Ricardo Salles.

Brazil is home to 60% of the Amazon, which is the world’s largest tropical rainforest and is seen as vital to the global fight against climate change.

While the final text of the EU-Mercosur deal has not been released, an outline from the EU states the agreement includes a provision that the Paris agreement on climate change must be effectively implemented along with other commitments to fight deforestation.

The French president, Emmanuel Macron, had warned last week before agreement on the deal that he would not sign off on it if Brazil leaves the Paris accord.

Paulo Adario, a Greenpeace forest strategist, said “all indications” were that deforestation will worsen under Bolsonaro, but he hoped news of a large increase would put pressure on the government to take action.

“When they have the final numbers, if it is really a lot, this will be a nightmare for Bolsonaro,” Adario said. “This is something that is really important from an international and Brazilian point of view because the Amazon is an icon.”