WASHINGTON — President Donald Trump said Monday the U.S. would begin “cutting off, or substantially reducing” aid to three Central American nations over a migrant caravan heading to the U.S. southern border. Trump tweeted: “Guatemala, Honduras and El Salvador were not able to do the job of stopping people from leaving their country and coming illegally to the U.S.” The three countries received a combined more than $500 million in funding from the U.S.