Apprehensions of foreigners just inside the Mexico-US border averaged about 43,000 a month in FY18, up from 35,000 a month in FY17. Apprehensions surged in FY19, topping 144,000 in May 2019 and prompting President Trump to threaten tariffs on Mexican goods if the Mexican government did not do more to prevent the entry and transit through Mexico of Central American families seeking asylum in the US. Apprehensions fell in June 2019.