Panic erupted among migrants, who had been marching in a caravan, after they were approached by members of Mexico's security forces near Frontera Hidalgo in the southern state of Chiapas. Some 800 migrants, mainly from Central America, who surged into Mexico on Thursday after wading across a river on the country's southern border with Guatemala, were detained by Mexican troops. Troops used tear gas and formed a human fence along a road to intercept the migrants, resulting in scuffles with some of the security forces. Following their detention, the migrants were taken to buses run by the National Migration Institute, the agency that will determine their official immigration status and manage deportations, the interior ministry said.