Author: David Agren, Special to USA TODAY

Mexico’s crackdown on fuel thefts has led to shortages across the country, leading to concern that trucks of avocados may not make it to the US

The two countries hope more aid to southern Mexico and Central America will persuade migrants to not make illegal, risky trip to U.S. southern border.

Migrant caravan: The first group is at the border. The majority are more than 1,000 miles away, and many more may stay in Mexico.

Migrants in a caravan set out Saturday on foot from Mexico City as more migrants in southern Mexico made way for Mexico’s capital.

Thousands of migrants will be on foot on Friday morning after failing to secure buses to get them to the U.S. southern border from Mexico City.

In Veracruz, about 4,000 migrants are stuck without promised buses to Mexico City. They are about 750 miles from nearest U.S. port of entry in Texas.

Mexico City places the immigrants about 600 miles from the closest U.S. border crossing in Brownsville, Texas. But the group may go to the California border.

Signs of division and frustration are emerging as caravan of migrants tries to get to the U.S.-Mexico border. A dangerous trek lies ahead.