Photo: Deccan Herald

Greece's largest migrant camp was partly evacuated early Wednesday after a major blaze broke out at the overcrowded and unsanitary home to nearly 13,000 asylum seekers.

Nearly the entire Moria camp on the island of Lesbos was on fire, including in an olive grove outside the walls of the main compound where many asylum seekers sleep in tents, an AFP photographer at the scene reported.

Asylum seekers were fleeing on foot toward the port town of Mytilene but were blocked by police vehicles, the photographer added.

Firefighters said earlier there were "scattered fires" around and inside the camp, which has a nominal capacity for fewer than 2,800 people.

Stand by Me Lesvos, a refugee support group, said on Twitter it had received reports that Greek locals on the island had blocked fleeing asylum seekers from heading into a nearby village.