Six young Afghan men including two minors were expected to face a prosecutor on Greeceís Lesvos island Wednesday on suspicion of setting fires to the Moria refugee camp last week.
The fire destroyed what was Europeís largest migrant camp, leaving close to 13,000 people without shelter.
The suspects, aged 20 and below, are all Afghan nationals and were arrested in the past few days, local officials told Greeceís Athens News Agency (ANA).
Greek officials had insisted from the start that the fires had been the result of arson.
Earlier Wednesday, 13 migrants were detained on the island of Samos after a fire broke out near the local camp that houses over 4,700 people.
Most were later released but three remain under questioning, a local police source told AFP.