Immigrants sit and lie under the international bridge at a migrant camp on the US-Mexico border on Tuesday in Del Rio, Texas. Photo: AFP

Thousands of mostly Central American migrants trekking across southern Mexico on Wednesday advanced only a short distance, with children and painfully blistered feet, the latest human caravan seeking to reach either Mexico City or the US border.

The mass of men, women and children left the village of Huixtla early in the morning, walking about 16 kilometers north along a local highway to the town of Villa Comaltitlan, in Mexico's southern Chiapas state, witnesses told Reuters.

"We haven't had any problems with immigration officials. God is opening doors for us," said a hopeful Julio Gonzalez, a Honduran migrant who spent Tuesday night sleeping near a street in Huixtla with his wife and two children under a steady rain.

In Villa Comaltitlan, some migrants told Reuters they sought to rest before departing early Thursday morning, which was especially important due to the large number of young children with them.

The latest migrant caravan has not yet faced off with Mexican migration agents or soldiers who have increasingly used tough tactics to stem the tide of fleeing migrants, many of whom want to escape violent gangs and grinding joblessness back home. The US has registered record levels of migration in 2021, as border agents have apprehended or expelled more than 1.7 million migrants over the past 12 months.

The majority of the latest caravan is families with young children, according to a witness who estimated at least 2,000 migrants had gathered on Tuesday in Huixtla to rest and receive medical attention before resuming their journey north.

Among them was Arleth Chavez from Guatemala, who had walked with the caravan for about 45 kilometers since it departed the southern border city of Tapachula over the weekend. "My feet are burning and in pain from the blisters," said Chavez, who nonetheless expressed a determination to continue.

Migrants have denounced the lengthy asylum process in Tapachula, located near Mexico's border with Guatemala, and thousands have departed the city in a series of caravans in 2021.