Greece’s largest migrant camp, Moria facility on the island of Lesbos, caught fire and engulfed the site.
However, there were no immediate reports of casualties as at least 25 firefighters with 10 engines battled the flames.
One eyewitness said the main compound, as well as makeshift shelters in a nearby olive grove, were ablaze.
Migrants were being evacuated from the facility which is home to nearly 13,000 people, more than four times the number it can officially hold.
As yet the cause of the blaze is unclear as one resident, Thanasis Voulgarakis describes the devastating scenery left behind by the fire.
“Now with the first light I can see that there is a few tents that make it, they are okay, but the rest of the camp, as I can see from this distance, is burnt out,” Voulgarakis said.
The camp was placed under quarantine last week after a migrant tested positive for the coronavirus.
Currently, there are now 35 confirmed cases.
Greek news agency, ANA, said the fires had broken out after some of the 35 had refused to move into isolation with their families, but this is unconfirmed.
Furthermore, the refugee support group Stand by Me Lesvos said it had heard reports of some locals attacking and preventing migrants from passing through a nearby village.
Reports from the scene said police have blocked migrants fleeing the fire from heading to the port town of Mytilene.