Dozens of men, women and children were killed in a crash in southern Mexico on Thursday. Most of the victims were migrants and asylum seekers from Guatemala.

At least 54 people died and more than 100 others were injured when a trailer overturned on the highway near Tuxtla, Chiapas. More than 160 people, mainly from Guatemala, were packed inside at the time of the crash.

President Andrés Manuel López Obrador called the accident tragic and said he hopes it pushes the United states to finally address the root causes of migration in Central America.

"We haven't been able to get them to address the causes migrants," López Obrador said during a press conference Friday, adding that U.S. leaders have been slow to respond to his proposals to improve conditions in the area.

However, migrant advocates say tragedies like this one also stem from hardened migration enforcement policies in both the United States and Mexico that put migrants in greater danger.

Under López Obrador, Mexico has increased its own migration enforcement efforts, including deploying the military to its northern and southern borders to contain migration, which has resulted in shocking images of abuse by immigration officials and national guard toward migrants in southern Mexico.

The accident also comes just a day after the United States relaunched the so-called “Remain in Mexico” program, which was initially implemented during the Trump administration. The program forces asylum seekers to wait in Mexico while their cases proceed through U.S. courts, and has been highly criticized because of the violence and unsafe conditions migrants face in Mexico.