The president pointed to the lawlessness at the US border after dozens of migrants were found dead in Texas

Mexican President Andres Manuel Lopez Obrador has warned that the US government is struggling to manage its southern border, blaming a "lack of control" after more than 50 immigrants died while being smuggled into the country, the deadliest human trafficking case in modern US history.

Speaking during a Tuesday press briefing - one day after dozens of migrants were found dead inside a tractor trailer near San Antonio, Texas - Obrador said the deaths were a "tremendous tragedy," adding that such incidents occur due to poverty and desperation, as well as the chaotic environment along the border.

"It happens because there is 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. 

US law enforcement officials told CBS the incident "appears to be the deadliest human smuggling case in modern US history," after the local authorities in Texas raised the death toll to 51 on Tuesday afternoon. It is unclear how long the group remained in the truck, but police said there were no signs of water or a working air conditioner in the vehicle despite scorching summer temperatures.

Though all the victims have yet to be identified, 39 men and 12 women were among the deceased, including migrants from Mexico, Honduras, and Guatemala. Another 12 adults and four children were taken to hospitals for treatment, all suffering heat-related ailments.

Three suspects have been detained in connection to the deaths, believed to have taken part in the smuggling operation which brought the victims into the US, according to an Immigration and Customs Enforcement (ICE) spokesperson.

Obrador went on to say that he would meet with US President Joe Biden on July 12 to discuss the border issue, arguing that the tragedy in Texas is "bitter proof" that solutions are needed.

"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 said.