Demonstrators gathered in the Mexican capital, Mexico City, to protest against President Andres Manuel Lopez Obrador’s plan to reform the national electoral college.
The organizers of the protest announced that more than 500,000 people attended the gathering in Zocalo Square.
Government sources put the number of demonstrators at 90,000.
On Wednesday, the Mexican Congress approved a major overhaul of the National Electoral Institute (INE), which Obrador has accused of being “inefficient”.
Obrador rejects claims that the changes will weaken Mexican democracy.
