Mexican security forces guard the riverside in Ciudad Hidalgo, Mexico on Jan. 21. REUTERS/ANDRES MARTINEZ CASARES Though United States (US) PresidentDonald Trump’s promised border wall has not been built, the number of migrantscrossing the southern US border has dropped sharply as Mexico stepped up thepolicing of its borders under the threat of punitive US tariffs.(Reuters) Mexico’s National Migration Institutesaid it deported 219 migrants to Honduras by plane in two separate flights. Foreign Minister Marcelo Ebrard saidaround 1,000 people managed to cross the country’s southern border on Mondayfrom Guatemala. MEXICO City – The government here onTuesday said it halted a caravan of undocumented Central American migrants whowaded across a river into Mexico. The caravan, part of a group ofseveral thousand people, last week fled rampant gang violence and dire jobprospects in Honduras.