Caravan of more than a thousand migrants sets out through southern Mexico towards the US, as Trump warns of doubled tariffs

More than a thousand migrants have begun marching through southern Mexico towards the US border, encouraged by the Democrats' victory in the midterm elections, while Mexican authorities blocked a second, smaller group from trying to reach the US.

The caravan, called 'God With Us', set off on Tuesday from Tapachula, near the Guatemalan border, and was en route on Wednesday, according to the Reuters news agency.

A Chiapas state government source estimated about 1,500 people were taking part, including many families, with parents carrying small children in their arms, in strollers or on their shoulders.

The migrants, mostly from Central America, aim first to reach Mexico City, more than 1,000km (621 miles) away, a journey likely to take at least several weeks, to seek help from the Mexican government and protection from detention.

Tapachula is a key transit point for migrants heading to the US, and thousands have become stranded there because of US entry restrictions and deportations, with few jobs, little healthcare and limited access to schools.

US President Donald Trump warned Mexico on Thursday that it must stop the group of migrants travelling through the country towards the US border or face a doubling of tariffs. 'Huge CARAVANS are forming and beginning their illegal march through Mexico,' he wrote on Truth Social.

Trump said a 'perceived loss' by his Republican Party in last week's midterm elections had emboldened the migrants, and that he was putting the incoming Democratic governor of the border state of Texas on notice about the issue.

Republicans lost control of the House of Representatives and the Senate in the midterm elections, with Democrats flipping multiple seats in both chambers. Voters delivered a rebuke of Trump in part for his immigration policies, and migrants in the caravan said the result gave them new hope.

Among the unusual Democratic victories was the governorship of Texas, which went to Gina Hinojosa, a woman of Mexican-American descent and the first Latina to lead the state.

'There might be a light at the end of the tunnel, a way for us to get in,' said Cesar Sandoval, a 47-year-old Nicaraguan who was deported from the US a few months ago. 'We believe the Democrats will help us,' he added.

On Tuesday, Mexico's National Guard, immigration authorities and police in Chiapas moved to stop a separate group of about 100 Central American migrants who had crossed the Suchiate River from Guatemala, the AFP news agency reported. Local footage showed officers positioned across a road as the migrants ran while surrounded; about 40 were detained, according to reports from Tapachula.

The larger group of about 1,000 had crossed on Sunday evening without resistance. It is the third caravan to try to reach the US since September, AFP said; the other two were broken up before leaving Chiapas, and their members were given temporary stay permits.

'As long as Trump remains president, the deportations will not stop,' said Ivan Porraz, a researcher at the College of the Southern Border.