Frantic relatives headed to the Athens morgue Thursday to seek the fate of loved ones still missing after Greece's deadliest forest fire in decades, a blaze that Greek authorities said they increasingly suspect resulted from arson.

Those arriving at the morgue were being informed of the necessary steps to match the missing and the dead, including providing DNA samples and dental records.

Greece Prime Minister Alexis Tsipras declared three days of mourning over the “unspeakable tragedy.”

Many tourists and residents fled toward the coastline to escape the ferocious flames and choking smoke.