Thousands of migrants head to Mexico City seeking U.S. asylum

STORY: The migrants, mostly Venezuelans, started their march north early in Tapachula, the city bordering Guatemala whose detention centers have been overwhelmed by their vast numbers.

Fleeing violence and poverty in Central America, thousands of migrants walk together for safety to Mexico each year, crossing several states in hopes of finding a legal route into the United States.

The new caravan has about 3,000 migrants, some from China and other Asian countries, Tapachula authorities estimated.