Hundreds of Central American migrants from a caravan that crossed Mexico reunited in Tijuana on Wednesday and planned to cross the border together this weekend in defiance of threats by U.S. President Donald Trump to repel them. The timing of the migrants arrival could compromise a flurry of talks this week to renegotiate the North American Free Trade Agreement (NAFTA), which Trump has repeatedly threatened to scrap if Mexico does not crack down on the flow of Central Americans through its territory. Busloads of migrants began arriving on Tuesday at a shelter that was a five minute-walk from the border...