Thousands of marchers wearing pink and white, the colours of the electoral body, filled Mexico City’s central square, the Zocalo, according to images broadcast on Milenio TV, which said that people were protesting in more than 100 cities. Mexicans abroad protested as well, including in Madrid. Protesters carried signs with the message, “Do not touch my vote.”

López Obrador’s reform seeks to reduce funding for the INE, as the electoral body is known, and trim its workforce. The regulator and electoral court are untrustworthy, the president, also known as Amlo, has said.

The Senate passed the electoral bill on February 22 after the government failed to pass a broader reform that required changing the Constitution. The original proposal included changes to how electoral authorities are chosen.

“Here in this Zocalo there is hope,” Beatriz Pages, a protest organiser and a former legislator for the PRI party, said in a speech at the Mexico City protest broadcast on Milenio TV. Pages called on demonstrators to join her in “a long, long battle for democracy”.

Senator Josefina Eugenia Vázquez Mota and lower house legislator Santiago Creel, both of the opposition PAN party, posted photos of themselves at the Mexico City demonstration on their respective Twitter accounts.

The opposition, which denounces the reform as an attempt to tamper with next year’s elections, will ask the Supreme Court to annul the legislation, arguing that it requires a two-thirds majority in congress to bypass the Constitution.