"You are not alone," was the message tens of thousands of supporters sent to striking teachers in Oaxaca during a massive demonstration in Mexico City on Sunday.

Protesters marched against the government's violent response to the teacher strikes and other dissension, as well as Mexican President Enrique Peña Nieto's neoliberal policies that spurred the educator protests and emboldened a wider backlash against his regime of privatization and repression—fueling many calls for his resignation.

Four thousand police were reportedly deployed across the city Sunday to counter the demonstration.

Sunday's march was called by Andres Manuel Lopez Obrador, the former mayor of Mexico City and the leader of the progressive Morena party, who posted a video to his Facebook page last week asking people to denounce the controversial education reforms, as well as the "political mafia" and "hypocritical conservatives" in the country.

According to TeleSUR, the former presidential candidate also posed a question directly to the government of Peña Nieto: "Why not choose humanism? Why not search for reconciliation and peace?"

The protest, which came one week after Mexican police opened fire on a roadblock in Oaxaca, marks an escalation in the fight that has rattled southern Mexico for over a year.

Teachers affiliated with the dissident Coordinadora Nacional de Trabajadores de la Educación (CNTE) union have been protesting new education mandates since last May. Last week, more than 200,000 doctors and other medical staff joined in a 24-hour strike against the government's attempts to privatize the federal social security and health systems. At the same time, students at major universities across the country boycotted classes to show support for the teachers as well as "oppose the ongoing efforts by the government to increase costs of higher education," TeleSUR reports.

With limited reporting, many shared images of the massive demonstration on social media. After the march, Lopez Obrador thanked the thousands who took part, saying: "Thank you for supporting the teachers and the teachers of Mexico. It became evident that they are not alone."

Quick recap: Mexico City on Sunday as thousands of people went out to support teachers against neoliberal bullshit. pic.twitter.com/83g1eaF8YV — Dirty Thirty Tony (@MexicAnarchist) June 27, 2016