FILE - In this Feb. 9, 2021 file photo, Mexican President Andres Manuel Lopez Obrador applauds during a ceremony at Chapultepec Castle in Mexico City. Mexico announced Saturday, April 24, 2021, that Lopez Obrador will hold talks with U.S. Vice President Kamala Harris on May 7 to discuss migration, amid an increase in underage migrants at the U.S. southern border. (AP Photo/Marco Ugarte, File)

Irma del Socorro Moo Ek, a beneficiary of Planting Life, a jobs and reforestation program promoted by Mexican President Andres Manuel Lopez Obrador, holds seedlings for planting, in Kopoma, Yucatan state, Mexico, Thursday, April 22, 2021. President Lopez Obrador is making a strong push for his oft-questioned tree-planting program, trying to get the United States to help fund expansion of the program into Central America as a way to stem migration. (AP Photo/Martin Zetina)

Vice President Kamala Harris, accompanied by President Joe Biden, speaks Tuesday, April 20, 2021, at the White House in Washington. Mexico announced Saturday, April 24, that President Andres Manuel Lopez Obrador will hold talks with Harris on May 7 to discuss migration, amid an increase in underage migrants at the U.S. southern border. (AP Photo/Evan Vucci)