TUXTLA GUTI?RREZ, Mexico, Aug 6, 2025 (BSS/AFP) - An activist known for leading massive migrant marches across Mexico to the US border -- and had planned one for Wednesday -- was detained Tuesday in southern Mexico, security officials said.

Luis Garcia Villagran was arrested and held in Tapachula, in the southern state of Chiapas, where the march had planned to depart for Mexico City on Wednesday.

The NGO Pueblos Sin Fronteras (People Without Borders) said the purpose of the march was to demand swift processing of paperwork for foreigners stranded in southern Mexico.

Pueblos Sin Fronteras director Irineo Mujica demanded Garcia Villagran's release, saying in a statement that he faces charges of organized crime.

The NGO said Garcia Villagran was detained by federal agents after meeting with migrants who planned to participate in the march.

The prosecutor's office did not immediately respond to a request for confirmation of the detention, charges or other details from AFP.

Garcia Villagran and Mujica have both been linked to organizing migrant caravans, some with thousands of Central Americans and Venezuelans, and attempting to reach the border to cross into the United States.

In November 2021, during one such march, then-US ambassador Ken Salazar accused the activists of profiting from their marches.

Reports of Garcia Villagran's arrest triggered fear among migrants organizing for Wednesday's march, who alerted each other of the situation using WhatsApp.

"Hide, don't let yourselves get caught," one such message seen by AFP said.

In recent decades, countless migrants have traveled across Mexico from its southern border, seeking to cross into the United States, along a route where they face abuse by authorities and criminals alike.