The trial of nine suspected smugglers held responsible for a 2023 boat disaster which killed hundreds of migrants in the Mediterranean began in the Greek port city of Kalamata on Tuesday.
Clashes reportedly broke out outside the courthouse between police and several dozen protesters campaigning for migrants' rights.
Only 104 people survived the June 2023 disaster south-west of Greece, which is believed to have killed up to 600 migrants.
The Greek public prosecutor's office said the accused - nine Egyptian men aged between 20 and 40 years old who were on board the ship - were identified by survivors as smugglers.
The defence has argued that the men were passengers on the boat, which set off from the Libyan port of Tobruk.
It has also questioned whether the Greek court has jurisdiction in the case, as the disaster occurred in international waters in one of the deepest parts of the Mediterranean.
The tragedy has been the source of controversy, with the Greek coastguard accused of failing to assist the vessel despite calls for assistance.
Greek officials said they had offered to help the boat and tow it to safety, but that the crew had denied assistance as it sought to reach Italy rather than Greece.
Witness reports have been conflicting. Some survivors said the coastguard did attend the scene and attempt to tow the boat, leading panic to break out on board and causing it to sink.
Other witnesses said the situation on the vessel deteriorated without intervention by the coastguard. Most of the hundreds of passengers were trapped below deck and were unable to free themselves as the boat sank.