Central American migrants arrive to a sports center during the annual Migrant Stations of the Cross caravan or “Via crucis,” organized by the “Pueblo Sin Fronteras” activist group, in Matias Romero, Oaxaca state, Mexico, Monday, April 2, 2018. A Mexican government official said the caravans are tolerated because migrants have a right under Mexican law to request asylum in Mexico or to request a humanitarian visa allowing travel to the U.S. border to seek asylum in the United States. (AP Photo/Felix Marquez)
Central American migrants from Honduras sing their national anthem during the annual Migrant Stations of the Cross caravan or “Via crucis,” organized by the “Pueblo Sin Fronteras” activist group, as the group makes a few-days stop in Matias Romero, Oaxaca state, Mexico, Monday, April 2, 2018. While a group of about a couple of hundred men in the march broke off and hopped a freight train north on Sunday, the rest seem unlikely to move until Wednesday or Thursday, and are probably going to take buses to the last scheduled stop for the caravan, a migrant rights symposium in central Puebla state. (AP Photo/Felix Marquez)
MEXICO CITY — President Donald Trump is warning about “caravans” of migrants heading to the U.S., though the caravan of Central American migrants supposedly moving across Mexico toward the border was strikingly immobile Monday.