A truck carrying US border crossing cards was hijacked in northern Mexico and the documents stolen, the US Embassy has confirmed.
In a statement Wednesday, the US said the theft happened on June 7, but did not specify where in northern Mexico it took place.
Authorities said the so-called "laser visas" would show up as stolen if anyone attempted to use them to cross into the United States. The crossing cards operate as visas for short-term trips to US border areas by Mexican holders in the border region, usually for day or shopping trips.
Arturo Montaño, spokesman at the US Embassy in Mexico City, told VICE News he could not confirm the location of the hijacking. "What's been stolen has been reported as such," he said.
Local reports, however, said the hijacking took place in the Tamaulipas state border city of Matamoros, across from Brownsville, Texas. The northeastern region of Mexico has seen persistent drug-cartel warfare related to smuggling routes into the United States.
US officials did not specify how many visas were stolen. The vehicle was moving the cards from the United States to consulates in the Mexican cities of Guadalajara and Monterrey. Visas were re-issued for the intended holders, the statement said.
The US Embassy and its consulates in Mexico this week warned visa applicants in the country about delays due to "technical problems" in the US global visa system. It was unclear if the delays were related to the truck theft.
Officials in Mexico City have apologized for the inconveniences to visa applicants.
The Associated Press Contributed to this report.