Most governments celebrate when their citizens are nominated for Academy Awards – but not in Jair Bolsonaro’s Brazil.

In an extraordinary barrage of tweets on Monday, the presidential agency responsible for elevating Brazil’s international profile savaged documentary director Petra Costa, branding her “an anti-Brazil activist” who had “tarnished the country’s image abroad”.

Bolsonaro’s politician son, Eduardo, led the charge, calling Costa a “canalha” – which translates roughly as “scumbag”.

Costa’s Netflix film The Edge of Democracy was nominated for the best documentary Oscar last month, and the 36-year-old filmmaker has become a prominent international critic of Bolsonaro’s far-right administration.

The immediate trigger for the presidential attack – which Brazilian experts called unconstitutional – was an interview Costa gave to the American journalist Hari Sreenivasan last week.

In it, Costa laments Bolsonaro’s fake news-fuelled rise to power and criticises the former army captain’s encouragement of Amazon deforestation and police killings, which she said had risen 20% in Rio de Janeiro state since Bolsonaro’s election.

Bolsonaro loyalists and relatives took exception to those remarks.

“I don’t usually waste time rebutting scumbags like Mrs Petra Costa but the level of her absurdities is criminal,” tweeted Eduardo Bolsonaro, the South American representative of Steve Bannon’s far-right group The Movement, alongside the hashtag #PetraCostaLiar.

Then came a volley of tweets from Secom – Brazil’s supposedly apolitical presidential communication secretariat.

“It is unbelievable that a film-maker can create a narrative full of lies and absurd forecasts in order to denigrate a nation just because she does not accept the result of elections,” the presidential agency tweeted in English.

“Without the slightest sense of respect for her homeland and for the Brazilian people, Petra said in an unreasonable script that the Amazon will become a savannah soon, and that President Bolsonaro orders the murdering of African Americans and homosexuals.”

In a Portuguese-language video, Secom rejected Costa’s claims about a spike in police killings as “fake news”. In fact, the claim is accurate. Official statistics show Rio police killed 1,810 people last year – the highest number in more than two decades and an 18% increase compared to 2018.

Secom also dismissed Costa’s claim that the Amazon “was already at a tipping point where it could become a savannah at any moment”. Leading scientists warn deforestation is pushing the Amazon rainforest towards an irreversible tipping point, although it is not clear precisely how soon.

Dilma Rousseff, the former leftist president whose controversial impeachment is the focus of Costa’s documentary, was among those who came to the film-maker’s defense, attacking the Bolsonaro government’s “intolerable aggression”.

It was Brazil’s far-right president, not Costa who was an “anti-Brazil activist”, Rousseff tweeted. “There is no-one in our country who is more anti-Brazil and more harmful to our overseas image than Bolsonaro.”

Alluding to Costa’s portrayal of Bolsonaro’s government, Rousseff added: “Petra was even serene in her choice of words, in expressing just a fraction of what Brazilians and the world already know: that Brazil is governed by a sexist, racist, homophobic, enemy of culture, supporter of dictatorships, torture and police violence and a pal of the paramilitaries.”

Last month Bolsonaro dismissed Costa’s film – which he admitted he had not seen – as “crap”.