At least 20 migrants have been found dead in a lorry abandoned in a motorway lay-by near the eastern border with Hungary, the Austrian authorities say.
The number of dead could be as high as 50, police say.
The grim find comes as a summit focusing on migration takes place in the Austrian capital, Vienna.
Tens of thousands of migrants from conflict-hit states in the Middle East and Africa have been trying to make their way to Europe.
The Emergency Election Sale is now live! Get 30% to 60% off our most popular products today!