Updated

A Brazilian supreme court judge said Friday that President Jair Bolsonaro and his Justice Ministry had five days to respond to opposition assertions that a recently passed gun decree was unconstitutional.

The decree presented on May 7 widely loosens the country's strict gun laws by expanding the ability of Brazilians to sell, access and carry firearms, in a move that some critics have qualified as "the most devastating gun reform" in decades.

Igarape, a Brazilian think tank, said this "death decree" considerably increases the number of people that could carry firearms without prior authorization from the federal police, further increasing violence in the world's leader in total annual homicides.

A day after Bolsonaro signed his decree, surrounded by supporting lawmakers who made finger-gun gestures with their hands, the Sustainability Network party filed a petition with the Supreme Federal Tribunal.

In the document, the political party argues the decree constitutes an "abuse of regulatory power by the executive" and that it should have been passed by Congress. They say Brazil's Constitution stipulates that it is for Congress to legislate on the possession, carrying and registering of firearms.

The decree's measures "clearly go against the spirit of the Disarmament Statute," the Sustainability Network party wrote, referring to the existing 2003 law on firearms.

Both the Senate and lower house agreed. The decree is "invading the prerogatives of parliamentary members," House Speaker Rodrigo Maia sai d Wednesday, asking for the reversal of specific points.

Bolsonaro said Friday that if the decree was unconstitutional, it should cease to exist. But hours later, he told an enthusiastic crowd in the state of Parana: "We are not retreating in front of those that since forever have said they are security experts."

Bolsonaro insisted he had acted within the limits of the law. "The life of a good citizen has no price."

Bolsonaro, a former army captain and congressman for 27 years, has long opposed the 2003 Disarmament Statute, which imposed a minimum age for possession of 25 and included mandatory background checks and requirements to renew licenses every five years.

During his time in Congress, Bolsonaro was part of the pro-gun lobby known as the "bullet caucus".

Among the decree's major changes, is the increase in the quantity of ammunitions available to gun owners. Under the new rules, they can buy between 1,000 and 5,000 rounds of ammunition a year, depending on their licenses, up from just 50 rounds.

Brazilians can now own up to four guns without requiring formal clearance from authorities and also have access to higher calibers, so far restricted to trained members of the armed forces, Igarape said.

New categories of people that can access guns thanks to the new decree and without authorization from the federal police include shooting instructors, collectors, hunters, tax collectors, bus and truck drivers, elected officials, lawyers, rural residents, journalists working with police and private security guards.

The impact of the decree in rural Brazil, Latin America's largest nation, could be major, analysts say.

Under the new rules, Igarape estimates that some 18.6 million "rural residents" and hundreds of thousands of hunters and collectors could access and carry firearms more easily and under less supervision.

Robert Muggah, Igarape's research director, says he expects "a dramatic increase in the circulation of firearms in northern, northeastern and midwest Brazil," where are concentrated many of the disputes between landowners and indigenous communities.

Loosening Brazil's strict gun laws and offering more protection to rural landowners were campaign promises of Bolsonaro, who promised to get tough on criminals and protect Brazilians from rising crime.

In 2017, 63,880 people were killed in Brazil, according the think-tank Brazilian Public Security Forum, making it the deadliest year in the country's history.