MYTILENE, Greece — Four Afghan migrants have been charged with arson for alleged involvement in fires that destroyed most of a large refugee camp on the eastern island of Lesbos, Greek authorities said. 

The men, who have not been named, were led to a court on the island on Wednesday to be formally charged. They were later returned to police detention after being given three days to prepare their testimony. 

The fires swept through the overcrowded camp at Moria last week, prompting more than 12,000 migrants and refugees to flee. Nobody was hurt. Most of them remain without shelter, camped on a roadside near the gutted camp.

Two other migrants allegedly involved in setting the fires are underage, and are being held by police on the Greek mainland. They have not been formally charged.

The government maintains that the fires at Moria were set deliberately by migrants protesting confinement after the site was locked down due to an outbreak of COVID-19.

Athens on Tuesday urged the European Union to jointly run new refugee camps on Greece's eastern islands as part of an overhaul of the EU's migration policies.