Demonstrators calling for an end to the Gaza war protested the arrival of an Israeli cruise ship on the Greek island of Crete on Tuesday.
It was the third such protest on Greek islands in the past week.
On the southern Greek island, protesters at the port of Agios Nikolaos unfurled a huge Palestinian flag.
They chanted “Free, free Palestine” as tourists aboard the Crown Iris disembarked and boarded buses for their excursions, according to images shown on local media outlets.
Riot police kept the crowd away from the pier where the cruise ship was docked, while scuffles broke out between demonstrators and police.
Local media reported that officers used pepper spray at one point to keep the crowd back.
Four people were detained, local media said.
Video footage showed police leading one man away, his arms cuffed behind his back, as he shouted “Free, free Palestine.”
Similar scenes unfolded the previous day when the Crown Iris docked in a port on the eastern Greek island of Rhodes.
Clashes broke out between riot police and demonstrators calling for an end to the war in Gaza.
There also, the cruise ship’s passengers disembarked for tours of the island, and no violence was reported.
Anti-war protesters on Greece’s Cycladic island of Syros were the first to hold a demonstration against the docking of the Crown Iris, on 22 July.
The crowd of about 150 people chanted slogans and carried banners that read “Stop the Genocide” and “No a/c in hell” — a reference to the conditions Palestinians face in the Gaza Strip.
On that occasion, the ship’s roughly 1,700 passengers did not disembark and the ship left the island earlier than planned.
The company operating the trip, Israel’s Mano Cruise, said it had “decided in light of the situation in the city of Syros to now sail to another tourist destination”.
Last week’s incident had triggered a phone call by Israeli Foreign Minister Gideon Saar to Greek counterpart George Gerapetritis.
Greece is a popular tourist destination for Israelis on package tours and traveling independently, particularly in the summer months.
There are several flights per day between Tel Aviv and Athens, as well as from Israeli airports directly to Greek islands.
