Outgoing President Donald Trump made tightening the southern frontier against what he called the free and dangerous flow of people entering the US from Mexico and Central America a key pillar of his US-centric policy on immigration, including his fitful plan to build a border wall.

Biden spoke Saturday with President Andres Manuel Lopez Obrador and emphasised “the need to reinvigorate US-Mexico cooperation to ensure safe and orderly migration,” the Biden transition team said in a statement.

“The two leaders noted a shared desire to address the root causes of migration in El Salvador, Guatemala, Honduras, and southern Mexico and to build a future of greater opportunity and security for the region,” the team said.

The border is a major crossing point for migrants fleeing poverty, drug-related violence and other woes in Mexico and Central America.

Lopez Obrador, a leftist, had cordial relations with Trump but it was only this week that he finally congratulated Biden on his win in the Nov 3 US election.