PARNDORF, Austria (AP) — Police on Thursday discovered the partially decomposed bodies at least 20 migrants piled up in a truck parked on the shoulder of an Austrian highway leading from the Hungarian border.

Police official Hans Peter Doskozil said the truck had Hungarian license plates. The state of the bodies made establishing the identity and exact number of dead migrants difficult, but the total number could rise to 50, said Doskozil, chief of Burgenland police.

He said the truck was apparently abandoned Wednesday and its back door was left open, exposing the bodies to police.

Police ordered reporters converging on the scene about 25 miles (40 kilometers) southeast of Vienna, to move away from the vehicle, a white refrigeration truck with images of food items on it.

Interior Minister Johanna Mikl-Leitner condemned the traffickers.

"Human smugglers are criminals," she said in a statement. "Those who still think that they are gentle helpers of refugees are beyond saving."