Image copyright AFP Image caption Migrants from Central America and other non-Mexican countries wait to cross into the US border in Tecun Uman, Guatemala, at the Tapanatepec border crossing in 2017
At least 53 migrants have died when their truck crashed on a highway in the Mexican state of Tamaulipas, Mexican authorities say.
Fifty-five others were still missing and feared dead, the interior ministry said.
The exact number of migrants onboard is not known, though US officials said they believed there were “more than 200” in the vehicle.
A transport ministry official said the driver lost control, hit an electricity pole and then overturned, causing the deaths.
Image copyright AFP Image caption Arriving migrants are taken to a processing centre run by migrants’ rights group Proactiva Open Arms Image caption Migrants are put on trucks while they wait to cross
Local media reports say 63 people were left behind on the highway – a section of which was closed off after the accident.
The death toll means it is the deadliest incident involving migrants trying to cross the Mexican border into the US in recent memory.
Many of those migrants have fled violence, poverty and persecution in Central America.
Mexico has issued a statement expressing “deep sympathy” to the families of those killed and calling on the US authorities to “continue seeking guarantees for the safety of the migrants, and the effective preservation of the privacy of the relatives of those missing”.
The vehicle – which police said was transporting migrants from El Salvador, Guatemala and Honduras – was an older four-wheel drive vehicle which should have had a number plate, the ministry said.
Tamaulipas state government spokesman Reinoso Varela told the AFP news agency that the truck had been travelling “very fast”.
He added that security forces had found “some migrants” but many were feared dead.
The official death toll from the accident was raised from eight.
Photos taken from a helicopter and posted on Twitter by the region’s governor in Tamaulipas, Egidio Torre Cantu, showed the area cordoned off with police and emergency workers.
Deaths from accidents have increased in the past several years as more migrants attempt to travel to the US illegally.
Mexico’s president Enrique Pena Nieto urged his government to send humanitarian aid to the area to help the survivors.
Image copyright Getty Images Image caption President Donald Trump has blasted Mexico for not doing enough to curb illegal immigration and urged its cooperation
In March, a bus travelling from the city of Juarez to El Paso in Texas fell into a swollen river in Tamaulipas, killing at least 43 people.
Last November, a bus plunged into a river, killing 19 people.
US President Donald Trump has repeatedly berated Mexico for not doing enough to curb the influx of migrants into the US.
In July, US Secretary of State Mike Pompeo made a trip to Mexico where he pressed President Pena Nieto to “do more” on the issue.