A passenger bus and a freight train collided at a grade crossing in northern Mexico on Friday, killing at least 16 people and injuring 22, a Mexican official said.

The official said the accident occurred in the town of Anahuac, which is Tamaulipas state near the border city of Nuevo Laredo, across from Laredo, Texas. The official was not authorized to be quoted by name.

The train's operator, Kansas City Southern de Mexico, issued a statement confirming there had been "a lamentable accident" between one of its trains and a passenger bus at about 5:25 p.m. The company said its employees reported "an undetermined number of dead and injured at the scene."

Kansas City Southern did not give a cause for the crash. The Mexican official said investigators were looking into whether the bus driver tried to beat the train to the crossing.

The train was operated by the Transporte Frontera line on a route from Nuevo Laredo to the neighboring state of Coahuila.