On Sunday, the group of mostly Central American and Caribbean migrants had walked 15km from the southern border city Tapachula to get to Alvaro Obregon, with plans to set off again around 4am the next day.

Migrant rights activist Luis Garcia Villagran urged that migrants must not become political bargaining chips in the upcoming presidential election in the US, where migrants were heading.

“We won’t be stopped, we’ll keep walking,” he said.

Local authorities estimated the size of the caravan to average about 8,000 people per day. A Reuters witness travelling with the group said most migrants were from Central and South America but also the Caribbean.

Haitian migrant Ysguel Jean, who was carrying a white cross with “Christ” painted in red letters, said he had left his home country because of rampant crime and corruption, and because he wanted to provide for his two daughters.

“Three months in Tapachula trying to get papers, and I still have nothing,” he said. “I’m tired of waiting around in Tapachula, being hungry, and unable to earn a living.” Like others, he said he wanted to reach the US.

In 2018 and 2019, large caravans mostly comprised of Central Americans, crossed Mexico to reach the US. These were followed by smaller groups in recent years.

Last year, record numbers of migrants attempted to cross the US-Mexico border illegally.