MEXICO CITY (Reuters) - Mexican rights groups and leftist President Andres Manuel Lopez Obrador’s opponents are pushing back against a sweeping new judicial reform designed to combat soaring crime, warning that the proposed changes threaten individual freedoms.

The reform is a cornerstone of Mexico’s attempts to get a grip on its unwieldy judicial system after a previous overhaul in 2016 failed to end rock-bottom conviction rates and record murder numbers.

Drafts of the proposed changes first reported by Reuters earlier in January include plans to allow private communications to be used as evidence and to limit legal challenges to avoid extradition delays for suspects, two issues seen as vital to Mexico’s security partner, the United States.

The publication of the reforms bill was delayed to February after the draft became public. Rights defenders are raising alarm bells about proposals that include an expanded use of preventive detention and could validate illegally obtained evidence.

“It is an extraordinarily regressive reform that seriously threatens human rights and processes given as basic, such as presumption of innocence,” said independent Senator and rights activist Emilio Alvarez.

“It is surprising that a government that identifies with the left presents such an authoritarian model of justice.”

In part, the reforms are aimed at addressing concerns by authorities that the 2016 switch to a U.S.-style accusatorial system made it harder for ill-prepared police and prosecutors to make cases stick.

They would also remove obstacles long criticized for gumming up criminal proceedings.

Many Mexicans have lost faith in the justice system. Murder rates hit a record high of 34,582 deaths last year, while less than one in 10 homicides results in a conviction.

Mexico’s prosecutor’s office on Wednesday said it will present a bill in February “to resolve the grave situation which exists in the country.” It distanced itself from the draft bills, saying they had not been signed off by the attorney general.

It was not clear whether the government will change the drafts before presenting them to Congress.

In earlier comments, Attorney General Alejandro Gertz told lawmakers the reform would create a single criminal code, replacing 32 state and regional codes. He said the goal was to end corruption, crime and impunity.

The government did not respond to a request for comment.

The proposals seek to restrict legal challenges known as amparos to avoid delaying extraditions, something used to draw out the legal process of several drug traffickers, including Joaquín “El Chapo” Guzman, currently serving a life sentence in the United States.

Also concerning activists is a proposal that would allow “illicit” evidence to “be taken into consideration and evaluated” by a judge, raising fears that wiretaps without warrants and even torture could be used in trials.

Mexico’s National Human Rights Commission (CNDH) said it was alarmed by a proposal to allow detention of suspects for 40 days without trial on corruption and “socially linked” cases, previously only permitted with organized crime cases.

Article 19, a freedom of speech group, said the proposed reform would “modify the justice system with alarming setbacks in terms of freedom of expression and information.”