An Algerian migrant was killed Friday when the roof of an abandoned warehouse collapsed in Patras, a port in western Greece where many migrants live in squalid conditions, police said.
Two men were also injured at the disused warehouse -- until recently used as a coastguard detention centre -- which was due to be demolished in September.
There had been repeated warnings about its stability, officials said.
"Migrants would enter the building to charge their cellphones as the power had not been cut," a police source told AFP. "Three people were there today."
Greece's third-largest city, Patras is a gateway to Italy for migrants hoping to sneak on to trucks and ferries.
Greece is housing around 60,000 mainly Syrian and Afghan refugees and migrants in camps around the country.
Many have become desperate to be allowed to continue their journey after several EU states shut down their borders last year, while others fear they will be deported to Turkey.