Police have reinforced several points of the Mexican capital to prevent hundreds of protesting teachers from following through on a threat to march to the international airport.
More than 4000 police were taking part in the operation launched early on Friday to contain the teachers, who reject an education overhaul enacted in 2013 by President Enrique Pena Nieto.
Hundreds of members of the militant CNTE teachers union went to the headquarters of the Government Secretariat in Mexico City to demand the start of a negotiation process.
The union's leaders had threatened to march to the airport and cut off all access routes to it if the government refused to agree to immediately begin talks on Friday.
But police prevented the protesters from carrying out their threat and kept them contained on a downtown thoroughfare, near the Government Secretariat.
Teachers with the CNTE, one of Mexico's most powerful unions with nearly 200,000 members, began a protest on May 15 in Mexico City to press for a roll-back of the overhaul.
The next day, they launched an indefinite strike in the states of Chiapas, Guerrero, Michoacan and Oaxaca.
The CNTE opposes new federally mandated teacher evaluations that are part of a sweeping education overhaul enacted in 2013 over the strenuous opposition of the teachers union.
