At least 46 migrants were found dead inside a semi-truck in San Antonio, Texas on Monday, authorities said.

According to CNN, authorities were alerted about the truck's contents just before 6 p.m., when a person working in a nearby building heard a cry for help inside the vehicle found near Lackland Air Force Base in San Antonio.

San Antonio Police Chief Bill McManus said the worker found the doors partially opened and saw several people deceased inside. 

First responders rushed 16 people - 12 adults and four children - into nearby medical facilities. All those found alive and deceased were reportedly migrants seeking a better life in the United States.

Migrants Likely Died From Heat and Lack of Water, Texas Fire Chief Says

San Antonio Fire Chief Charles Hood said those still alive were hot to the touch and were suffering from heat stroke and exhaustion. 

Hoos noted that the migrants found alive were still conscious when transported for care. Hood also said that while the tractor-trailer was refrigerated, there was no visible working air condition unit, nor was there any sign of water for the people being transported.

The National Weather Service reported high temperatures within the San Antonio area where the truck was found. It ranged from the high 90s to low 100s on Monday.

Officials remained hopeful that the migrants who survived the ordeal will recover. They also said three of those rushed to the nearby Methodist Hospital Metropolitan were now in stable condition. 

According to McManus, three people have been taken into police custody. However, it is still unclear whether they are connected to the situation.

Milenio reported that the San Antonio Police Department is now looking for the driver of the truck. The Department of Homeland Security (DHS) has also dispatched several investigators to the scene.

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Texas Governor Greg Abbott Blames Joe Biden for Migrants' Deaths; San Antonio Mayor Mourns

In a tweet, Texas Governor Greg Abbott spoke about the deaths of the migrants. Abbott said "these deaths are on" President Joe Biden. The governor blamed Biden's open border policies and said the deaths were consequences of the president's refusal to enforce the law.

But according to New York Daily News, the tweet did not go too well to many, as Abbott was lambasted in replies.

Many pointed out that this was all Abbott's fault because despite the governor's beefing up security along the Texas-Mexico border and increasing the funding for the human trafficking unit, migrants were still able to get across the border on his watch. 

The Texas governor is currently running on an anti-immigration platform for his re-election bid and has focused his attacks on Biden. 

But while Abbott has been playing partisan politics in the face of the tragedy, San Antonio Mayor Ron Nirenberg lamented the deaths of 46 migrants, calling it a "horrific human tragedy." He mourned the tragedy, urging people to think compassionately and asked to pray for the deceased, the ailing, and their families.

Mexican Foreign Secretary Marcelo Ebrard also expressed condolences to the victims' families on his Twitter account.

Ebrard said the Mexican consul general in San Antonio, Ruben Minutti, was already verifying the nationality of the deceased. And if there are Mexican nationals among the victims, he noted that support would be provided to the victims and their families.

The nationalities of all the victims were still unknown. But some media outlets reported that some of the victims are from Guatemala and Honduras.

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This article is owned by Latin Post.

Written by: Rick Martin

WATCH: At Least 46 People Found Dead in Semi Truck in Texas - From NBC News