Mexican President Andres Manuel Lopez Obrador said his government would reinforce measures to contain migration as he sought to help the United States cope with record numbers of people trying to reach the US border.
Lopez Obrador's comments come a day after he spoke with US President Joe Biden, during which both agreed that more enforcement was needed at their shared frontier as record numbers of migrants disrupt border trade.
"What was agreed is that we keep working together," Lopez Obrador told a regular press conference. "We have a proposal to strengthen our plans, what we've been doing," he added, without going into details.
Migrants are heading through Mexico to the US to escape violence, economic distress and negative impacts of climate change, according to the UN. The number crossing the dangerous Darien Gap straddling Colombia and Central America has topped half a million this year, double last year's record.
The latest tensions over the border flared up after Mexican authorities temporarily stopped expelling migrants due to an end-of-year funding crunch, according to officials.
After Lopez Obrador spoke, the government of Mexico's Coahuila state announced in a statement it had sent a planeload of migrants from Piedras Negras, across the border from Eagle Pass, Texas, to Villahermosa, in the southern state of Tabasco to be returned to their countries of origin.
The statement did not specify the number of migrants on the Boeing 737 or whether more flights were planned, but it said the effort was coordinated with Mexico's national migration agency.
Top US officials, including Secretary of State Antony Blinken and Homeland Security chief Alejandro Mayorkas, will visit Mexico on Wednesday to follow up on the call, Lopez Obrador said, calling current migratory pressures "extraordinary".
"Above all, the number of Venezuelan migrants," he said, also mentioning Haitians, Cubans and Ecuadorians.
Lopez Obrador said Mexico would step up containment efforts on its southern border with Guatemala as his government seeks agreements with other countries to manage the northbound migrant flows.
Measures under discussion did not just involve containment, Lopez Obrador said, adding it was important to continue efforts to promote economic development in the region and address the root causes of migration.
The veteran leftist stressed he would continue to call for talks between the US and Cuba, which has been under an American economic embargo for decades, and that discussions on easing US sanctions on Venezuela were "progressing."
He said containment needed to be complemented by political moves to lower regional tensions with Venezuela and Cuba, as well as Guatemala, which has been roiled by efforts to prevent the president-elect from taking office in January.
"Because one way or another, all of this encourages migration," he said.