MEXICO CITY — Migrants in a caravan that drew criticism from U.S. President Donald Trump began packing up their meager possessions and boarding buses to Mexico City and the nearby city of Puebla on Thursday.

The migrants had been camped out at a sports field in southern Oaxaca since the weekend. Trump had said they were marching toward the U.S. border, though that was never among the organizers' plans.

Trump wrote on his Twitter account Thursday that "the Caravan is largely broken up thanks to the strong immigration laws of Mexico and their willingness to use them so as not to cause a giant scene at our Border."

On Thursday, one bus left the camp before dawn en route to the central city of Puebla, where organizers hope to hold a migrants' rights symposium. Another left at midmorning carrying migrants to Mexico City, where some want to set up meetings with international organizations to talk about the plight of migrants fleeing violence and poverty.

At its height last week, the caravan consisted of almost 1,500 people mostly from Central America. Many have been given temporary transit visas which they intend to use to request asylum in the United States.

Others say they plan to ask for humanitarian visas to stay in Mexico.

Mexican Interior Minister Alfonso Navarrete Prida said Thursday the government was granting the humanitarian visas "to guarantee humane treatment to those women who were pregnant or had small children."

Navarrete Prida said the migrants had decided to disperse, not because of pressure from the U.S. or Mexican government. "This wasn't the product of a tweet," he said.

"The decision to demobilize a caravan isn't in the hands of the government, it is up to the migrants themselves," he said. "Every time the different levels of government have tried to stop the caravans in past years, and they have happened for more than ten years, it has been met with resistance, it backfired," Navarrete Pride said. "It wouldn't have been possible to dissolve this year's caravan if it wasn't a decision by the migrants themselves."