Three people have been arrested after more than 40 bodies of migrants were found dead in a truck in Texas.
Authorities are currently at the scene in southwestern San Antonio, where a truck with 46 people dead inside was found, fire chief Charles Hood confirmed.
Sixteen people who were found alive, including 12 adults and four children, have been rushed to hospital.
At least 44 migrants have been found dead inside a large truck in San Antonio. (Supplied) The truck was located next to the railway tracks (Supplied)
Survivors were suffering heat-related injuries, Hood added.
The truck was found next to railroad tracks in a remote area of San Antonio.
San Antonio Police Chief William McManus said a nearby worker heard a scream for help around 5pm Texas time (8.00am Sydney time) and went to investigate.
“They found a trailer with the doors partially open and opened them to take a look at it and found several dead people inside,” McManus said.
Hood said a body was found outside the truck and the rest were found inside the trailer.
San Antonio Police Chief William McManus addresses migrant deaths. (Supplied)
McManus said three people have been arrested, but it is unclear whether they are “absolutely connected or not.”
He added that it is now a federal investigation.
McManus confirmed that this is one of the deadliest human trafficking incidents in the city’s history.
It’s unclear how people died, but Texas cities have experienced a heat wave throughout June with temperatures exceeding 39 degrees.
San Antonio Mayor Ron Nirenberg called it a “horrible human tragedy.”
“We hope that those responsible for putting these people in such inhumane conditions will be prosecuted to the fullest extent of the law,” he said.
Mexican Foreign Minister Marcelo Ebrard posted on Twitter confirming that the consul was going to the scene, but the nationality of the victims is still unknown.
“Tragedy in Texas. It is reported that they suffocated inside a trailer,” Ebrard said.
“Consul en route to the site.
“Condolences to the victims and their families.”
Police block the scene where a semi-trailer with several bodies was discovered in San Antonio. (AP)
Texan Gov. Greg Abbott posted on Twitter blaming U.S. President Joe Biden for the deaths.
“These deaths are in Biden. They are the result of his deadly open-border policies,” Abbott wrote.
“They show the deadly consequences of their refusal to enforce the law.”