Texas residents gathered under a scorching sun Wednesday to mourn the 53 migrants who died this week after they were abandoned in a trailer in soaring temperatures, leaving tokens of flowers, candles and bottles of water.

The mourners, several of whom said they or their loved ones had also migrated to the United States illegally, gathered at the site in San Antonio where the truck was found on Monday to erect large wooden crosses and pay their respects.

Immigration authorities have said 53 people died, many of dehydration and heatstroke after they were shut inside the trailer with no water during a day when ambient temperatures rose to 103 degrees Fahrenheit (39.4 degrees Celsius).

A large-scale emergency operation was launched at the scene involving police, firefighters and ambulances
A large-scale emergency operation was launched at the scene involving police, firefighters and ambulances GETTY IMAGES NORTH AMERICA via AFP / Jordan Vonderhaar

Eleven others are still being treated in local hospitals, authorities said.

"All of this breaks my heart because I have family who have been through the same thing," said Veronica Vazquez, 37.

"All my cousins, my uncles, came to the United States illegally, some over the river and others through the desert," she said.

People place flowers, candles and water bottles at a makeshift memorial to the 53 migrants who died after being abandoned by smugglers in a tractor-trailer near San Antonio, Texas.
People place flowers, candles and water bottles at a makeshift memorial to the 53 migrants who died after being abandoned by smugglers in a tractor-trailer near San Antonio, Texas. AFP / CHANDAN KHANNA

Roberto Alvarez, who lives in the area, brought roses and candles.

The 48-year-old himself came to the United States as an undocumented immigrant.

"You put yourself a little bit in their place... because you also lived through it," he said.

Maria Lopez (C) cries as she visits a makeshift memorial to the 53 people migrants who died near San Antonio after being abandoned by traffickers in an overheated tractor-trailer.
Maria Lopez (C) cries as she visits a makeshift memorial to the 53 people migrants who died near San Antonio after being abandoned by traffickers in an overheated tractor-trailer. AFP / CHANDAN KHANNA

According to Francisco Garduno, head of Mexico's National Migration Institute, the dead included 27 Mexicans, 14 Hondurans, seven Guatemalans, and two Salvadorans.

The nationalities of the other three were not yet revealed.

Four men have been arrested and charged over the incident so far, according to a statement from the district attorney's office of western Texas.

A large-scale emergency operation involving police, firefighters and ambulances was set in play after dozens of dead bodies were found in a tracter-trailor in San Antonio, Texas
A large-scale emergency operation involving police, firefighters and ambulances was set in play after dozens of dead bodies were found in a tracter-trailor in San Antonio, Texas GETTY IMAGES NORTH AMERICA via AFP / Jordan Vonderhaar

The office said a 45-year-old named Homero Zamorano had been arrested at the scene, where he was spotted "hiding in the brush after attempting to abscond."

He was also spotted on surveillance footage driving the truck at an immigration checkpoint, the statement said, adding that he has been charged with one count of alien smuggling resulting in death, and faces life in prison or execution if convicted.

Garduno said the suspected driver had initially pretended to be one of the survivors.

The local daily San Antonio Express-News reported the man was "very high on meth," citing a law enforcement officer.

Federal law enforcement agents arrested two other men Tuesday at the address linked to the tractor-trailer's registration, court documents showed.

Juan Francisco D'Luna-Bilbao and Juan Claudio D'Luna-Mendez, both Mexican nationals who overstayed US tourist visas, were charged with illegal possession of multiple firearms, the documents alleged. They face up to ten years in prison.

The fourth man, Christian Martinez, was arrested in eastern Texas on Tuesday, the district attorney's statement said.

He was charged with one count of conspiracy to transport illegal aliens resulting in death, and also faces life in prison or potentially the death penalty, it said.

Officials from Mexico, Guatemala and Honduras, who met at Mexico's embassy in Washington, issued a joint statement in which they pledged to help the victims and their families.

They said that they would form a rapid action group to target and dismantle human trafficking networks.

San Antonio police were first alerted to the trailer on Monday, after a worker near an isolated road in San Antonio heard a cry for help and went to investigate.