Wooden crosses, in memory of migrants who died crossing to the U.S., lean on the border fence in Nogales, Sonora state, Mexico, Nov. 10, 2016.

A Mexican migrant talks to a family member through the border fence between Ciudad Juarez and El Paso, Texas, following a bi-national Mass on Feb. 15, 2016. The Mass was organized to bring together dozens of families of Mexican migrants living in the U.S. and who, based on their immigration status, were not able to join their families in Mexico when Pope Francis celebrated the Mass in Ciudad Juarez on Feb. 17, 2016.

People are seen on the Mexican side of the U.S. border wall dividing a beach in Tijuana, Mexico, April 10, 2016.

A newly built section of the U.S.-Mexico border wall at Sunland Park, New Mexico. The photo was taken on Nov. 9, 2016, from the Mexican side.

The border fence separates the towns of Nogales, Mexico, and Nogales, Arizona.

U.S. Border Patrol agents from Boulevard Station, whose nickname is the "East County Regulators," head out on patrol near Jacumba, California, Nov. 14, 2016.

A U.S. Border Patrol agent opens a gate in the fence along the Mexico border to allow vehicles pass in El Paso, Texas, Jan. 17, 2017.

A Mexican boy watches U.S. workers building a section of the U.S.-Mexico border wall at Sunland Park, New Mexico, opposite the Mexican border city of Ciudad Juarez, Sept. 9, 2016.