President Donald J. Trump warned Mexico on Thursday that tariffs on Mexican goods would be “IMMEDIATELY DOUBLED” if the country does not stop migrant caravans moving north toward the United States.

“Huge CARAVANS are forming and beginning their illegal march through Mexico,” the president wrote on Truth Social shortly after 7 a.m. Eastern time. “Many of the people in these Caravans are those that various countries don’t want - ‘Send them to America,’ they say - But they will not be accepted! MEXICO MUST STOP THEM, NOW, and if they do not do so, the Tariffs on Mexico will be IMMEDIATELY DOUBLED.”

The president wrote that Mexico, the governor of Texas, the state’s incoming governor, “OUR GREAT BORDER PATROL, & ICE, HAVE BEEN SO INFORMED.” He added: “There will be no leniency!”

A group of about 1,500 migrants, mostly from Central America, set out on Tuesday from Tapachula, a city in southern Mexico near the Guatemalan border, Reuters reported. The Mexican government did not immediately issue a statement in response to the president’s warning, Anadolu Agency reported.