U.S. President Donald Trump's sweeping foreign aid freeze has stalled a United Nations program in Mexico aimed at stopping imported fentanyl chemicals from reaching the country's drug cartels, according to eight people familiar with the situation. It’s one of several U.S. counternarcotics efforts in Mexico derailed in recent weeks by the stop-work order.The initiative provided Mexico’s Navy with training and equipment to improve screening of cargo entering and exiting the Port of Manzanillo…
