Image copyright EPA Image caption The men were detained at a secret migrant camp in Veracruz, Mexico
Police in Mexico have detained 600 migrants hidden in two trailers at a makeshift migrant camp near the US border.
Officials raided the camps at New Port Huachuca and Cimitan on the border with Guatemala, Mexico’s National Migration Institute (INM) said.
The migrants were arrested while applying for refugee status, the INM said.
It comes after the US border patrol killed a teenage boy with an electric shock stun gun in the area last month.
Who are the migrants?
There are generally between 4,000 and 5,000 people arriving daily in Cimitan, about 40km from the border, according to human rights group Pueblo Sin Fronteras (People Without Borders).
They are mostly from Central America who have travelled a long way to reach the border, known as “The Dirty Corridor”.
Most enter Mexico from Guatemala, but many are from El Salvador, Honduras and Guatemala, which are plagued by gang violence and poor economic conditions.
The migrants are given a registration number and then placed in a camp set up by Pueblo Sin Fronteras, where they are offered food, water and medical care.
“We consider it normal that there are already more than 6,000 migrants in these unsanitary conditions with no water, electricity, toilets or anywhere to sleep. They also give us medical attention and also some legal advice,” Pueblo Sin Fronteras co-ordinator Marco Rubio said at the time.
The camp becomes more crowded during the day as day-trippers arrive at about 10am.
A huge container camp has been erected in the area, but some migrants are still living in a primitive manner, sleeping in a field and surviving on flour, soy beans and corn.
What’s happened to the migrants?
Clifford Ruiz was shot and killed by US Border Patrol (USBP) agents as he tried to cross the border in San Diego. Two other migrants were also shot dead.
The 18-year-old school dropout was running back and forth between the US and Mexico when he was killed.
Mexican officials have suggested that Mr Ruiz was likely an “illegal alien”, who had been deported previously.
It is not clear exactly why he and two other men – a 37-year-old Honduran and a 15-year-old Salvadoran – had been shot.
Mexican officials have never publicly questioned why US Border Patrol agents were carrying out searches in the area at the time and Mexico has demanded an explanation for their deaths.