Trump links US border wall to NAFTA renegotiation, warns Mexico 'must stop drug, people flows'

President Donald Trump on Sunday explicitly linked his proposal to build a barrier between the U.S. and Mexico to ongoing NAFTA negotiations, as he renewed a warning that the flow of illicit drugs and undocumented immigrants from the country "must stop."

Via Twitter, the president ripped the U.S.'s southern neighbor for doing "very little, if nothing" to stem illegal immigration and narcotics from flowing across the border. He repeated a threat he made earlier this year, warning that successful trade pact renegotiations may hinge on Mexico making efforts to secure its side of border.

Trump also took aim at the outlines of a deal to legalize the status of legions of illegal immigrants who arrived in the U.S. as children, and called on Congressional Republicans to exercise a "nuclear option" to toughen immigration. Last fall, Trump canceled the Deferred Action for Childhood Arrivals, colloquially referred to as DACA.