Thousands of people marched in Mexico on Sunday to support the country's electoral authority.

Demonstrators at the "March for Democracy" accuse President Andres Manuel Lopez Obrador, known as AMLO, of trying to weaken the authority ahead of an election in June.

Also on Sunday, presidential front-runner Claudia Sheinbaum officially registered as a candidate for the ruling Morena party. She has promised to largely maintain Lopez Obrador's policies.

Sheinbaum leads polls by 64%. Her biggest competitor, Xochitl Galvez, has polled at around 31%.

What else do we know about the protests?

Organizers said 700,000 people took part in the event. The protests were called for by Mexico's opposition parties.

In Mexico City, thousands of people dressed in pink and white rallied in the city's main square and chanted "get Lopez out."

On Friday, Lopez Obrador criticized the protests.

"They are calling the demonstration to defend corruption, they are looking for the return of the corrupt, although they say they care about democracy," he said.

Anti-AMLO protests come amid electoral reform proposal

The protests come after Lopez Obrador sent a proposal to reform the National Electoral Institute (INE) to Congress as part of various constitutional reforms.

One reform would shrink the number of counselors heading the body and would require electoral judges be elected by popular vote.

"Authorities are seeking to eliminate (autonomous institutions), to subordinate them or take them over," Lorenzo Cordova, the former head of the INE, said during a rally. "We've seen a ferocious attack against these institutions."

Lopez Obrador alleges the INE helped engineer his electoral defeats in 2006 and 2012. He has also attacked Mexico's judiciary, accusing judges of being part of a conservative conspiracy against his government.

Opponents have accused Mexico's president of taking aim at the INE in order to concentrate power in the ruling Morena party's hands.

sdi/lo (AP, Reuters, AFP)