Austria will step up deportations of migrants and is adding Morocco, Algeria, and other states to a list of countries it deems safe, enabling it to send people back there more quickly, government ministries said on Sunday.

The mass attacks on women in Cologne and other German cities on New Year’s Eve have prompted more than 500 criminal complaints, with Cologne investigations focused largely on asylum seekers or illegal migrants from north Africa, police have said.

Austrian police have discovered the badly-decomposing bodies of at least 20, and possibly up to 50, migrants piled in a truck parked on the shoulder of the main motorway from Budapest to Vienna.