Greek police on Friday prevented 1,000 Afghans from boarding a ferry trying to leave Lesbos island, where they were stranded for days.
Local media reported that the police attacked the Afghans with stun grenades when they tried to storm the ferry, Blue Star. EFE news reported.
The clashes stopped once the ferry's entrance was closed.
On Wednesday, Spyros Galinos, mayor of Lesbos, declared a state of emergency on the island due to the overwhelming influx of refugees and migrants.
In the first eight months of this year, 230,000 people seeking refuge arrived in Greece, including 150,000 in the months of July and August.
Most refugees come through the Aegean islands, because of its proximity to Turkey, which is the main gateway for many refugees to reach European Union countries.