Police and coast guards scuffled Wednesday with more than 150 supporters of monks from a rebel monastery in northern Greece.
Authorities said pilgrims at the port of Ouranoupolis were stopped from boarding a boat to the Orthodox Christian sanctuary of Mount Athos. No one was hurt in the incident.
The coast guard said the pilgrims were not carrying permits required to enter the monastic sanctuary.
The pilgrims support ultraconservative monks of the Esphigmenou monastery who are at odds with the other 19 monasteries on the peninsula over efforts to forge closer ties between Orthodox churches and The Vatican.
Late Tuesday, police also turned back five Esphigmenou pilgrims who were trying to enter the peninsula by land.
Esphigmenou monks, who are preparing to hold an annual religious celebration Thursday, have defied monastic authorities for more than 30 years.
Last year, at least seven people were hurt in clashes between rival groups of Athos monks who were wielding crowbars and sledgehammers.
Athos — a self-governing peninsula banned to all women — is revered as one of the most important sites of Orthodox Christianity.