ATHENS, Greece (AP) — Demonstrators gathered Thursday for a fourth consecutive day on the eastern Greek islands of Lesbos and Chios to protest government plans to build new migrant detention centers.

The protest comes amid heightened tensions on the islands that have felt the full impact of migrant flows from war-torn Syria in particular. On occasion, the tensions between the island residents and police have turned violent.

Shops and services were shut on Lesbos as workers extended an initial 24-hour strike into a second day as part of the protests. The mayors of Lesbos, Chios and the nearby island of Samos were to meet with Prime Minister Kyriakos Mitsotakis in Athens to discuss the situation.

Wednesday’s protests descended into violence, with hundreds of demonstrators attacking police guarding the building sites of future migrant detention camps on Chios and Lesbos. A crowd also laid siege for hours to a Lesbos army camp where riot squads were staying.

Officials have said 43 police officers were injured in violence in Lesbos, and another nine in Chios, where a mob burst into a hotel being used by riot police and beat officers resting in their rooms.

The government has said it will pull out many of the riot police deployed to the islands earlier this week.

Greece’s eastern Aegean Sea islands have been the main entry point into the European Union for tens of thousands of people fleeing conflict and poverty in the Middle East, Africa and Asia. Under a 2016 deal between the EU and Turkey, new arrivals must stay on the islands pending deportation back to Turkey until their asylum applications are processed.

Long delays in the asylum process and increased migrant flows have led to severe overcrowding in the island camps, which are several times over capacity.

Island residents have demanded that all migrants be moved to the mainland, and vehemently object to new camps being built in their areas.