Around 1,500 migrants have formed a caravan in southern Mexico and hope to make it to the U.S. before President-elect Trump takes office in January, when he is expected to clamp down heavily on illegal crossings which have soared under the Biden-Harris administration. 

The caravan, made up of men, women and young children mostly from Central and South America, on Wednesday traveled through the city of Tapachula, located in southern Mexico, just over the border from Guatemala where thousands of migrants are stranded because they do not have permission to cross further into Mexico.

The most southern point of the U.S. border is at the crossing at Matamoros, near Brownsville, Texas, and it would take a desperate adult migrant about 16 days of non-stop walking to get there. It is unclear exactly where members of this particular caravan they intend to cross.

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Migrants for caravans because they believe there is safety in numbers as it is hard or impossible for immigration agents to detain large groups of hundreds of migrants.

Some are hoping to catch rides to help them on their journey, while others will make the arduous trip to the southern border by foot in the searing heat.

"It is going to be more difficult, that’s why we are going in hopes of getting an appointment quicker so we are able to cross before he (Trump) takes office," Yotzeli Peña, 23, a migrant from Venezuela tells the Associated Press. "That would be easier."

Trump has promised to seal the southern border due to the unprecedented flow of migrants into the U.S. over the last three and a half years. 

He has also vowed to carry out the largest deportation operation in the history of the U.S. and has appointed hardliner South Dakota Gov. Kristi Noem to serve as secretary of the Department of Homeland Security (DHS) while Tom Homan will be the new "Border Czar." 

Additionally, he has also pledged to end the use of parole programs by the Biden administration that allow migrants to enter in via the expanded "lawful pathways."

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Numbers have been dropping sharply at the border since June, when President Biden signed a presidential proclamation drastically limiting the number of arrivals who can come into the U.S.

In September, there were 101,790 encounters at the border, the lowest number since February 2021, and there have been no major signs of a significant increase in numbers since then.

However, while numbers remain lower than in previous months, there have been concerns that the change in administrations may lead to a surge at the border as migrants attempt to enter the U.S. before a perceived tougher administration enters office. 

This year, in a bid to stop people from gathering at the U.S. southern border to claim asylum, the federal government expanded areas where migrants can apply via the CBP One cellphone app for appointments to enter the United States.

Initially, the app was only available to migrants in northern and central Mexico, but officials changed it to include those at the southern border.

By extending the app south to Tapachula, officials hoped it would stem the rush north. But some migrants still want to be close to the border so that if they do get one of the cherished appointments, they can get to it quickly and not risk missing it. 

"They’re determined to make it into the U.S., one way or the other, because they’ve sold everything, they have nothing to go back to," independent journalist Auden Cabello, who extensively covered the border crisis, told Fox News Digital last week. 

Fox News’ Adam Shaw, Michael Lee and The Associated Press contributed to this report.