Dozens of mostly Haitian migrants stranded in southern Mexico protested on Wednesday to demand the right to travel freely to the United States.
Around 200 people marched through the city of Tapachula near the border with Guatemala to the immigration office to ask for documents that would allow them to head north.
Mexican security forces have recently broken up several migrant caravans attempting the journey, prompting accusations of excessive use of force.
Rights activists are seeking a court order allowing the migrants to leave Tapachula, where thousands have been stranded for months without permission to cross Mexican territory.
Campaigners on Wednesday submitted five injunction requests for urgent cases to the federal courts, said Luis Garcia of the Center for Human Dignification.
"Today these families are going to go on foot, by bus or however they can towards the northern border," he told reporters.
Migrants stuck in Tapachula face overcrowding, inadequate healthcare and the risk of coronavirus infection, medical aid group Doctors Without Borders (MSF) said last week.
On Monday campaigners will seek permission for 7,000 migrants to travel in a caravan to Mexico City and demand a solution from President Andres Manuel Lopez Obrador, Garcia said.
"We're going to go to Mexico City no matter what. Tapachula is not a garbage dump," he added.
Activists including Garcia ended a 72-hour hunger strike they held to demand free transit and an end to the use of force against migrants.
The National Migration Institute (INM) recently suspended two of its agents for mistreating a Haitian migrant while dispersing one of the caravans.
Mexico has seen increased arrivals of migrants fleeing violence and poverty since US President Joe Biden took up residence in the White House with a promise of a more humane approach toward migrants.
Mexican authorities have arrested more than 147,000 undocumented migrants so far this year -- three times more than in the same period of 2020, according to the INM.