Police in Slovenia say they discovered 22 migrants hiding in two food-grade tanker trucks.
The migrants were found inside the trucks on Saturday at the border with Croatia, police said. The trucks had Serbian license plates.
Slovenian police said the people inside the tanks could have suffocated. They were from Bangladesh, India, Turkey and Syria, police said.
Officers first discovered 13 people in one truck at the border before searching another belonging to the same company, where they found nine more.
Thousands of migrants have been stuck in the Balkans while seeking ways to move toward Western Europe. They often rely on people smugglers to get them over borders illegally.