An overloaded van carrying 29 migrants crashed on a remote South Texas highway, killing at least 10 people including the driver, authorities said.
The crash happened on the US 281 in Encino, Texas, about 180 miles south of San Antonio.
Sergeant Nathan Brandley of the Texas Department of Public Safety said the van, designed to hold 15 passengers, was speeding as the driver tried to veer off the road onto Business Route 281.
A further 20 passengers were injured in the crash at around 4pm on Wednesday.
The van was not being pursued, authorities said.
Brooks County Sheriff Urbino Martinez said he believed all of the passengers were migrants.
The identities of the 30 in the van were being withheld until relatives can be notified, Sgt Brandley said, and no information about the van, including where it was registered or who owned it, was immediately released.
A surge in migrants crossing the border between the US and Mexico illegally has brought about an uptick in the number of crashes involving vehicles packed with migrants who pay large amounts to be smuggled into the country.
The Dallas Morning News has reported the recruitment of young drivers for the smuggling runs, combined with excessive speed and reckless driving by those youths, have led to horrific crashes.