TAPACHULA: Thousands of migrants left southern Mexico on Monday with the intention of heading to the United States, where the Summit of the Americas is starting this week with migration on the agenda.

Luis Garcia Villagran, coordinator at the Human Dignity Center NGO accompanying the caravan, said there would be “more than 15,000” people in the group, which AFP reporters watched depart the city of Tapachula.

“We say to the leaders of the countries that are today meeting at the Summit of the Americas, that migrant women and children, migrant families, we are not currency exchange for political and ideological interests,” said Garcia.

“We are walking for our freedom, because we have the right to migrate.”

US President Joe Biden, host of the summit being held in Los Angeles, is hoping to reach a regional agreement on migration.

His plans took a hit earlier Monday, however, when Mexican President Andres Manuel Lopez Obrador, whose country Central American migrant caravans pass through en route to the United States, announced he would not be attending the summit.

Lopez Obrador criticized the United States for refusing to invite Cuba, Nicaragua and Venezuela, countries Washington considers undemocratic and oppressive.

Migrants chanted “Freedom!” and “We want visas!” and carried small flags from Venezuela, Nicaragua and Honduras as they set off on the 3,000-kilometer (1,860-mile) journey to the US border.

“Migrants are not criminals, we’re international workers,” read one banner.

Migrant caravans that traversed Mexico in 2018 and 2019 sparked tensions with the administration of then-US president Donald Trump.

Since then, Mexico has stepped up its border controls and in 2021 more than 300,000 undocumented migrants were detained there.

Since Biden succeeded Trump in January 2021, the number of migrants attempting to reach the United States has increased.