Migrants set out from Mexico hoping to reach pre-Trump US

The group of about 1,500 people set out from Tapachula in southern Mexico in the early morning hours for a walk of some 2,600 kilometers (over 1,600 miles).

"My mentality is to get there, I want my (asylum) appointment before he (Trump) takes power," Colombian Yamel Enriquez told AFP.

"If I don't get the appointment before, I will give myself over to whatever God wants."

Venezuelan Zuleika Carreno joined the exodus with the same single-minded purpose.

She said she decided not to postpone her departure "for fear of getting stuck on this side" of the border, which would mean her laborious travels so far would have been "in vain."

Trump, who won an election in which illegal migration was a top issue, has vowed to declare a national emergency on border security and use the US military to carry out a mass deportation of undocumented migrants.

Authorities estimate that some 11 million people are living in the United States illegally, and Trump has stoked concerns by claiming an "invasion" is underway by migrants he says will rape and murder Americans.

On Wednesday, Mexican President Claudia Sheinbaum said her government was preparing a document highlighting the contribution of workers from her country to the US economy.

Migrants who amass in Mexico from a variety of troubled countries with a view to a better life in the United States frequently organize group movements known as "caravans" in a bid to pressure authorities into giving them temporary Mexican visas.

Sticking together also reduces the risk of criminal attacks, but the migrants groups usually disperse along the way.