Mexico’s Senate has passed legislation that would transfer control of the country’s National Guard over to the military, a contentious move that rights groups and opposition lawmakers say gives too much power to the armed forces and could lead to abuses.

The Senate’s 71-51 vote in favour of the bill on Friday comes after the lower house of Congress already approved the measure. President Andres Manuel Lopez Obrador is expected to sign it into law.

When the National Guard was created under a constitutional reform in 2019, it was placed under civilian control – but most of its training and recruitment has been done from within the country’s military.

Lopez Obrador, commonly referred to as AMLO, has waved aside concerns over the increased militarisation of public security, saying the guard must now be under military command to prevent corruption.

But opposition parties have said they plan to file court appeals challenging the new legislation, which they argue violates the Constitutional guarantee on civilian control.

“Public safety is not achieved by violating the rule of law, by violating the Constitution,” said Senator Claudia Anaya Mota of the Institutional Revolutionary Party.

The Mexican military has been criticised for a record of abuses and rights groups have warned that removing civilian control over the National Guard could lead to similar violations.

“We have already seen the disastrous results of the militarization of public security forces in Mexico over the last 16 years,” Edith Olivares Ferreto, executive director of Amnesty International Mexico, said in a statement on Friday, criticising the Senate’s decision.

“We call on the executive branch to design a plan for the progressive withdrawal of the armed forces from the streets, prioritizing the strengthening of civilian police forces and the development of public prevention policies aimed at guaranteeing public safety.”

Nada Al-Nashif, the UN High Commissioner for Human Rights, also said that “the reforms effectively leave Mexico without a civilian police force at the federal level, and further consolidate the already prominent role of the armed forces in security in Mexico”.

“The security forces should be subordinated under civilian authorities,” Al-Nashif said in a statement.

But Lopez Obrador on Friday lashed out at critics, including the United Nations.

“When did the United Nations take a stand?” he said during a regular news conference, questioning what the body had done to prevent war from breaking out between Russia and Ukraine.

“These organisations that supposedly defend human rights, almost all these organisations are made up of people on the right from different countries of the world … because they earn a lot of money for simulating, for pretending, for being go-betweens for authoritarian governments,” he said.

Mexico has seen record levels of violence in recent years, and members of the opposition and activists have accused the National Guard of various cases of abuse.

The ranks of the National Guard, made up of more than 110,000 members, are largely filled with members of the army and marines. Those officers retained their place in the military and were considered on loan to the guard.

Before coming to power in 2018, Lopez Obrador had pledged to send the military back to the barracks. But he has tasked them with a wide variety of assignments, including fighting drug cartels, helping with various infrastructure projects, such as a new airport in the capital, and building bank branches in rural areas.

Late last month, a Truth Commission investigating the 2014 disappearance of 43 students said that six of the students were handed over to an army commander who ordered that they be killed. The shocking revelation directly tied the military to one of Mexico’s worst human rights scandals.