Nayib Bukele’s government has already locked up 2% of El Salvador’s adult population and built the largest prison in the Americas to house the 70,000 alleged gang members he has imprisoned.

Now the populist leader has cleared the way for mass trials of hundreds of people at a time as he steps up his year-long crackdown on the country’s gangs which critics say is eroding the rule of law and leading to many innocent people being wrongly jailed.

El Salvador’s congress passed a bill on Wednesday that could allow up to 900 people to be tried simultaneously if they come from the same region or are accused of belonging to the same criminal group.

The legislation also increases prison time for those found to be gang leaders from 45 years to 60.

A state of emergency declared in March 2022 means the right to trial is increasingly disregarded in the Central American country and the list of people held for months awaiting trial is growing quickly.

The latest blow could leave El Salvador’s justice system as little more than a facade, human rights groups said.

“All human beings deserve the opportunity to defend themselves in court. How can they do this effectively in group trials? How can lawyers and public defenders do their work this way?” said Carolina Jiménez Sandoval, president of the Washington Office on Latin America (Wola).

Bukele’s New Ideas party said the measure would help bring more order to the country as it seeks to stamp out its violent armed gangs. Congress approved the bill with 67 votes in favour and six against.

Bukele’s harsh approach to criminality has won the millennial leader the strongest approval ratings in Latin America and a cult following with politicians across the region who emulate his casual looks and hardline security policies to win over voters.

But critics say that the 42-year-old is sweeping aside democratic checks and balances.

More than 70,000 alleged gang members have been put behind bars in the last 16 months and the crackdown is increasingly indiscriminate.

A growing number of innocent foreign visitors are finding themselves in overcrowded Salvadorian jails after being rounded up by troops for having tattoos and being in poor neighbourhoods.

“These reports are becoming more common by the day from human rights organisations, people who have managed to leave jail and families denouncing arbitrary arrests,” said Ruth Elonaro López, a lawyer at Cristosal, a Salvadorian human rights group. “The problem is the state of emergency means there no longer needs to be evidence to detain or jail someone for long periods of time. People are being rounded up because they seem nervous, they have forgotten their documents or they are simply young.”

There appears to be no long-term plan for the one in 50 adults now imprisoned in dangerously overcrowded and unsanitary conditions.

The most notorious of El Salvador’s criminal organisations, the MS-13, grew inside Salvadorian prisons in the 1990s and 2000s after its founding members were deported there from the US.

More than 6,400 documented human rights abuses have been committed during Bukele’s state of emergency and 174 people have died in state custody, the Inter-American Commission on Human Rights said earlier this month.

The plan for mass trials will only make prison conditions worse and add to the list of innocent people held behind bars, Jiménez Sandoval said.

“It seems El Salvador has turned the presumption of innocence principle upside down. With this arbitrary policy everybody is a suspect and a potential criminal.”