Some 150 minors housed at the camp were evacuated to a children's village on the island, the police source said.

There are now over 60,000 refugees and migrants in Greece, most of them seeking to travel to Germany and other affluent EU countries.

But they are unable to do so after several eastern European and Balkan states shut their borders earlier this year.

Human rights groups have repeatedly criticised the condition of Greek migrant camps, pointing to overcrowding and unsanitary living conditions.

The situation is particularly acute on Lesbos and other eastern Aegean islands facing Turkey, where most of the migrants land and are held for registration.

According to government data, there are over 13,000 people on five islands in facilities built to house fewer than 8,000.

Brawls are common in the island camps, with many desperate to avoid being returned to Turkey or their home countries after spending a small fortune and risking their lives trying to escape poverty and persecution.