Deforestation in Brazil's Amazon rainforest doubled in January compared with a year ago, reaching a five-year record for the month, officials say.
Destruction at this time of the year tends to slow down as the rainy season makes access to areas more difficult.
But instead of falling to the same low levels as in the past, deforestation remained high, official data showed.
Critics say far-right President Jair Bolsonaro's policies and rhetoric encourage illegal activities.
Deforestation in the Amazon - a vital carbon store that slows down the pace of global warming - soared last year, the first of President Bolsonaro in office.
His environmental policies have been widely condemned, but he has rejected the criticism, saying Brazil remains an example for conservation.
More than 280 sq km (108 square miles) were cleared in January, an increase of 108% on January of last year, according to the space research agency Inpe - a record for the month since data started being collected in 2016. One square kilometre roughly equals 200 football pitches.
Climatologist Carlos Nobre, a scientist and researcher at São Paulo University (USP), said there was a risk that deforestation this year could surpass the level recorded in 2019. At the peak of the dry season last year - between July and September - destruction was above 1,000 sq km per month.
"It's very worrying the increase in January 2020. It suggests that the factors that caused the increase in deforestation in 2019 are still very active. It's time for an effective and comprehensive action to control and contain illegalities in the Amazon," he told G1 website (in Portuguese).
Mr Bolsonaro has previously criticised the environmental enforcement agency, Ibama, for what he described as excessive fines, and his first year in office saw a sharp drop in financial penalties being imposed for environmental violations. At the same time, the agency remains underfunded and understaffed.
One unnamed field operative for Ibama told Reuters news agency: "We see a huge difference [in deforestation]... We thought there would be a drop off because of the weather and all that, but it didn't happen."
Ibama and Brazil's environment ministry have not commented.
Meanwhile, on Wednesday, Mr Bolsonaro unveiled his project to open up protected indigenous reserves in the Amazon to activities including commercial mining and farming, a controversial plan that still needs to be approved by Congress.
Critics and environmental groups say Mr Bolsonaro's plans could further increase deforestation in the Amazon. Mr Bolsonaro, who has repeatedly criticised the size of indigenous reserves, says the economic development of those areas will benefit indigenous groups.
On Twitter, Joenia Wapichana, Brazil's sole indigenous congresswoman, said: "Mining on indigenous lands is illegal and unconstitutional... Mining only brings pollution and death. We don't want the deaths of rivers, the forest and indigenous peoples."
Mr Bolsonaro has also vowed to integrate indigenous people into the rest of the population, saying they live in poverty like "animals in zoos". Last month, he was criticised after saying indigenous people were "evolving" and becoming more human.
Also on Wednesday, Mr Bolsonaro named Ricardo Lopes Dias, a former missionary who worked with a group committed to opening churches on indigenous land, to head the office in charge of isolated tribes at the indigenous affairs agency, Funai.
The appointment was widely criticised by rights groups and Funai workers, amid fears it could signal a change to the government's traditional hands-off approach to the remote groups.