MEXICO CITY (Reuters) - More than 100 Central American migrants, including dozens of minors, were rescued from a truck found abandoned in a violent region of northern Mexico near the U.S. border, authorities said on Friday.

The migrants, from Honduras, Guatemala and El Salvador, were suffering from dehydration and asphyxiation when soldiers came across the truck in Tamaulipas, where migrants often attempt illegal border crossings.

Every year, thousands of Central Americans seeking to flee violence and poverty in their homeland use Mexico as a conduit to the United States, often transported by human traffickers in dangerous conditions that can be fatal.

Mexico’s migration institute INM said soldiers patrolling in the city of Camargo in Tamaulipas heard yells for help from within the truck’s trailer, where they discovered 103 migrants, including 36 minors, who had been crammed together for about 12 hours.

A photo sent by the INM appeared to show some of the migrants’ belongings in the back of the truck, including a small, pink backpack, duffel bags and trash strewn across the floor.

A dozen of the minors were traveling alone and will receive legal aid to apply for refugee status in Mexico, the INM said.

It did not specify when the migrants were found.

U.S. President Donald Trump on Friday urged Mexico to do more to prevent violent illegal immigrants from El Salvador from entering the United States, again pushing his long-proposed border wall but stopping short of his previous claims that Mexico would fund it.

In a Twitter post, Trump said U.S. law enforcement was removing Salvadoran gang members but that they continued to return, adding: “El Salvador just takes our money, and Mexico must help MORE with this problem. We need The Wall!”

More than 800 Central American migrants have been found in truck trailers or safe houses in Mexico so far this year, according to a government document seen by Reuters.

In July, 10 people died after a truck stuffed with more than 100 Guatemalan and Mexican migrants was abandoned in a Texas parking lot.