President Donald Trump gives a thumbs up to supporters as he arrives at WesBanco Arena during a Make America Great Again rally in Wheeling, West Virginia, U.S., September 29, 2018. REUTERS/Mike Theiler

WASHINGTON (Reuters) - U.S. President Donald Trump has approved a deal to update the North American Free Trade Agreement (NAFTA), keeping the trilateral pact with Canada and Mexico, a source familiar with the decision said on Sunday.