At least 120 people - 100 of them police officers - have been injured in clashes during anti-government protests in Mexico City, police said.

Thousands of demonstrators marched in the Mexican capital on Saturday to protest against violent crime and President Claudia Sheinbaum's government.

Sheinbaum said the marches, which also took place in other cities, had been funded by right-wing politicians who oppose her government.

The rally was organised by Gen Z youth groups, drawing support from citizens protesting against high-profile killings, including the assassination just weeks ago of Uruapan Mayor Carlos Manzo - who had called for tough action against cartels.

Demonstrators dismantled parts of a barrier protecting the National Palace, where Sheinbaum lives. Police protecting the compound used tear gas on the crowds.

Authorities have arrested 20 people for crimes including robbery and assault, Mexico City security chief Pablo Vazquez told reporters.

Protesters waved banners displaying messages including "We are all Carlos Manzo", while others wore cowboy hats in tribute to him.

Manzo was shot on 1 November while he attended a Day of the Dead festival.

He was known for speaking openly about drug-trafficking gangs in his town and cartel violence. 

He had been demanding tough action against armed cartel members who terrorise the country. 

Sheinbaum has been acting against cartels but resisting calls for another all-out war on drugs. Previous attempts by her predecessors have ended with bloody results.

Days before the march took place, the president said the demonstration was being promoted by bots online.

"We agree with freedom of expression and freedom of demonstration if there are young people who have demands, but the issue here is who is promoting the demonstration," she said in a briefing. 

"People should know how this demonstration was organised so that no one is used."

| Reuters (Pic): Some protesters paid tribute to Uruapan mayor Carlos Manzo

Sheinbaum retains approval ratings above 70% in her first year in office, and has made in-roads in clamping down on fentanyl-trafficking – a key issue for her US counterpart, Donald Trump.

But she has been criticised for failing to halt the violence gripping the country and is facing increased hostility from nearby countries.

Earlier this month, Peru's Congress voted to declare Sheinbaum a persona non grata - or unwelcome in the country.

The decision came days after Peru severed diplomatic ties with Mexico, after the Mexican government granted asylum to a former Peruvian prime minister facing charges for a 2022 coup attempt.