Four Americans who drove across the U.S.-Mexico border from Texas were fired upon, held at gunpoint and possibly kidnapped, according to the FBI.

Special Agent Oliver Rich, who is in charge of the FBI’s San Antonio Division, announced Sunday that the bureau is seeking public assistance to locate four U.S. citizens who were last seen in the northern Mexico border city of Matamoros, Tamaulipas. …

That day, “four Americans crossed into Matamoros, Tamaulipas, Mexico driving a white minivan with North Carolina license plates. Shortly after crossing into Mexico, unidentified gunmen fired upon the passengers in the vehicle. All four Americans were placed in a vehicle and taken from the scene by armed men,” the FBI said in a statement.