Police and other first responders work the scene, Texas, June 27, 2022. (AP)

Mexican President Andres Manuel Lopez Obrador has cautioned that the United States is struggling to manage its southern border, accusing it of "lack of control" after more than 50 immigrants were killed while being smuggled into the country.

The grim discovery was one of the worst disasters involving migrants in recent years, and it occurred five years after a similar deadly incident in the same central Texas city, just hours from the Mexican border.

During a press conference on Tuesday, one day after dozens of migrants were discovered dead inside a tractor-trailer near San Antonio, Texas, Obrador called what happened a "tremendous tragedy," adding that such incidents occur due to poverty and desperation, as well as the chaotic border environment.

“It happens because there is the trafficking of people and a lack of control, in this case at the Mexican-US border, but also in the US interior,” the president said.

Obrador divulged that he would meet US President Joe Biden on July 12 to tackle the border crisis, citing the Texas tragedy as "bitter proof" that solutions are required.

“We must continue to insist on supporting people so that they do not have to leave their villages to go look for life on the other side of the border,” he concluded.

"These deaths are on Biden"

Texas Governor Greg Abbott, a Republican who advocates for tough immigration policies, blamed the disaster on President Joe Biden's "deadly open border policies."

"These deaths are on Biden," Abbott tweeted. "They show the deadly consequences of his refusal to enforce the law."

On his account, Mexico's foreign minister Marcelo Ebrard called the incident a "tragedy" and stated that the Mexican consul was on his way to the scene.

The archbishop of San Antonio has also commented on the incident by saying: "once again, the lack of courage to deal with immigration reform is killing and destroying lives."

In 2017, a similar migrant tragedy occurred in San Antonio, when ten people died while traveling into the United States in a sweltering trailer with broken air conditioning and clogged ventilation holes.