Fact check: Trump says 'a lot of wall has been built' as he demands we build more

Contractors work to reinforce a section of the U.S. border wall in San Diego where scores of Central American migrants have crossed illegally in recent weeks, shot through the fence from Tijuana, Mexico.
Contractors work to reinforce a section of the U.S. border wall in San Diego where scores of Central American migrants have crossed illegally in recent weeks, shot through the fence from Tijuana, Mexico.