Authorities in the German city of Dresden have launched a major investigation after an Eritrean asylum seeker was found stabbed to death, a killing that comes amid tensions over immigration in the region.

The 20-year-old man was found dead Tuesday morning in front of the suburban apartment building where he lived. An autopsy showed he died from stab wounds to the neck and chest. Lorenz Haase, a spokesman for Dresden prosecutors, told news agency dpa Thursday that "the whole machinery prosecutors and police have available" is being put into the case.

There's no indication yet who might be responsible and Mayor Helma Orosz warned against speculation.

Dresden has seen growing weekly rallies recently by a group opposing what it calls the "Islamization of the West" that advocates tougher immigration rules.