More than 7,000 migrants have arrived on the island, which has a population of 30,000, thanks its proximity to Turkey.

After attempts to register them turned into a near riot that saw police spray people with fire extinguisher foam on Tuesday in Kos town, Kos’s mayor Giorgios Kyritsis warned the situation could quickly get worse.

He said: “This situation on the island is out of control. There is a real danger of uncontrollable situations. Blood will be shed.”

He also called for the Greek authorities to do more to help move migrants off the island as well as help police the ones already there.

Kyritsis said: “How many illegal immigrants can Kos cope with? How many can Greece cope with?”

The United Nations refugee organisation UNHCR has criticised the treatment of migrants on the island, adding as many as 3,000 may still be waiting to be registered by the authorities.