A fire broke out on Sunday at a container inside a crowded refugee camp on the eastern Greek island of Lesbos close to Turkey and at least one person was killed, emergency services said.
Refugees clashed with police as thick smoke rose over the Moria camp, which currently houses about 12,000 people in overcrowded conditions and firefighters fought to extinguish the blaze.
Police said one burned body was taken to hospital in the island's capital Mytilini for identification by the coroner.
Police sent reinforcements to the island to help restore order. They could not immediately reach an area of containers, where there were unconfirmed reports of another burned body.
Greece has been dealing with a resurgence in refugee and migrant flows in recent weeks from neighbouring Turkey. Nearly a million refugees fleeing war in Syria and migrants crossed from Turkey to Greece's islands in 2015.
More than 9,000 people arrived in August, the highest number in the three years since the European Union and Ankara implemented a deal to shut off the Aegean migrant route. More than 8,000 people have arrived so far in September.
Turks have also attempted to cross to Greece in recent years following a failed coup attempt against Turkish President Tayyip Erdogan in 2016.
On Friday, seven Turkish nationals, two women and five children, drowned when a boat carrying them capsized near Greece's Chios island.