The United Nations called for migrants crammed into a squalid camp on the Greek island of Lesbos to be immediately transferred to the mainland, following a fire in which a woman and a child were killed.
The UN's refugee agency described the situation in the Moria camp, where 13,000 people are living in a facility designed for 3,000, as "critical".
"We are calling to accelerate the transfers and improve conditions in Moria," said Boris Cheshirkov, the UNHCR's spokesman in Greece.
Stratos Kytelis, mayor of Lesbos, also demanded that asylum seekers were moved off the island, which lies in sight of the Turkish coast. The population has oscillated as groups are transferred to the mainland, only to be replaced by more asylum seekers.
Clashes erupted between asylum seekers and police on Sunday, after the blaze broke out in some of the shipping containers in which many migrants are housed. A woman and child died in the fire and at least 17 people were hurt.
Police fired tear gas to control asylum seekers, who accused the authorities of taking too long to respond.
Humanitarian organisations condemned the conditions in the camp, where Afghans, Syrians and other nationalities are forced to sleep in tents in olive groves.
