ATHENS — Greek authorities say 139 vulnerable asylum-seekers who had been living in overcrowded Greek island camps have left for Germany, as part of efforts to ease overcrowding and move refugees to other European countries.

The group that flew out of Greece on Wednesday consisted of children suffering serious health problems and their immediate families, as well as 53 unaccompanied minors, the migration ministry said.

The unaccompanied minors are part of a program for 1,600 children and teens up to 18 who are in Greece without their parents or guardians to be resettled in other European countries. 

Alternate Migration Minister Giorgos Koumoutsakos said the flight to Germany was the first resettlement flight after Greece's largest refugee camp, the notoriously overcrowded Moria camp on the island of Lesbos, burned down earlier this month. 

Greek authorities arrested six Afghans, including two unaccompanied minors, on suspicion of arson for the fires. Officials have said the blazes were deliberately set during protests against lockdown and isolation measures imposed to contain a coronavirus outbreak in the camp. 

Just over 26,000 refugees and migrants live in camps on islands, where they arrived after crossing from the nearby Turkish coast in smuggling boats. More than half are on Lesbos. 

On Tuesday, authorities moved nearly 1,000 refugees from eastern Aegean islands to the mainland to reduce overcrowding on the island refugee camps.

Officials said all unaccompanied teenagers and children living in camps on the islands or on Greece's land border with Turkey had been moved to appropriate facilities on the mainland.