Mexican President Andres Manuel Lopez Obrador led huge crowds of supporters on a march through the capital Sunday in a show of political strength by the left-wing populist.
The rally came as allies of Lopez Obrador, known by his initials AMLO, jockey for position ahead of the next presidential election in 2024, in which he cannot run.
Lopez Obrador, 69, was mobbed by supporters as he spent more than five hours walking a few kilometers (miles) through the crowds to Mexico City's main square, amid cries of "it's an honor to be with Obrador."
An estimated 1.2 million people joined the rally, according to presidential spokesman Jesus Ramirez, although there was no independent confirmation of that figure.
Lopez Obrador delivered a speech outlining what he considers to be the main accomplishments of his four years in office so far, including measures to alleviate poverty, improve public services and fight corruption.
Mariachi bands entertained the president's supporters, who arrived on buses from around the country, many wearing purple, the color of his Morena party.
"The president is not alone," read a placard at the rally, while others vowed support for the government's controversial electoral reform plan.
"I like the way AMLO governs, always doing everything for the most vulnerable," said Alma Perez, a 35-year-old teacher who traveled from the southern state of Guerrero to join the march.
Lopez Obrador "has done what no other president has done for the poor," said Ramon Suarez, a 33-year-old electrician.
"He has some areas in which to improve such as security, but that's not done overnight," Suarez added.
It was the first such march led by a Mexican president in at least four decades, according to experts.
The rally comes two weeks after tens of thousands joined an opposition protest against the president's proposed electoral reform.
Lopez Obrador wants to "show muscle," said Fernando Dworak, a political analyst at the Mexican Autonomous Institute of Technology.
"It was a serious mistake by the opposition to believe that the president can be beaten on the streets," he told AFP, referring to the November 13 anti-government protest.
Lopez Obrador, who enjoys an approval rating of nearly 60 percent, owes much of his popularity to his social welfare programs aimed at helping the elderly and disadvantaged Mexicans.
Mexican presidents are barred from serving more than one term, and Lopez Obrador again ruled out trying to change the constitution to stay in office.
"No to re-election," he told supporters.
At the same time, Lopez Obrador is keen to see his Morena party hold onto power after he stands aside.
Three of the president's allies and potential successors -- Mexico City Mayor Claudia Sheinbaum, Foreign Minister Marcelo Ebrard and Interior Minister Adan Augusto Lopez -- accompanied him at the rally.
Lopez Obrador knows "that in order for him to win elections, he needs oiled machinery that works all the time," said Gustavo Lopez, a political scientist at Tecnologico de Monterrey, a Mexican university.
Opposition parties accuse Lopez Obrador of being an "authoritarian" populist who is "militarizing" the country by giving a greater role to the armed forces in both security and infrastructure projects.
His efforts to revamp the independent National Electoral Institute (INE) have proven particularly controversial.
Lopez Obrador alleges that the INE endorsed fraud when he ran unsuccessfully for the presidency in 2006 and 2012, before winning in 2018.
He wants the organization to be replaced by a new body with members chosen by voters instead of lawmakers and with a smaller budget.
Critics see the plan as an attack on one of Mexico's most important democratic institutions.
The reform would require support from at least two-thirds of lawmakers in Congress, and Lopez Obrador's political opponents have vowed to oppose the changes.