ATHENS (Reuters) - Clashes broke out on Sunday between asylum-seekers and groups of locals on Lesbos, police said, in one of the most serious bouts of violence on the Greek island in months.

Locals were protesting against a group of about 200 refugees and migrants who had camped out for days on a main square on the island’s seaside promenade, a police official on the island said. The asylum-seekers were demonstrating against conditions in the island’s camp and delays in asylum applications.

Video footage on a local news website showed riot police moving in to disperse the crowd which had set several garbage containers on fire.

The clashes, which began on Sunday evening, lasted well into the early hours of Monday, the official said.

Media reported that far-right supporters were among the protesters. Lesbos Mayor Spiros Galinos described the protest as a “spontaneous reaction” but added: “If persons of extreme ideological beliefs took part in this reaction, it was to be expected.”

Lesbos was the main gateway to Europe for nearly a million refugees and migrants in 2015. Arrivals have slowed significantly since a European Union deal with Turkey in 2016 but a steady flow is putting pressure on island facilities.

Its main camp, Moria is holding more than double the number of people it was intended to.

“For the last three years, Lesbos has been experiencing an unprecedented situation. It’s carrying a huge burden,” Galinos told Greece’s Skai TV. “I’m trying to convince the government that Lesbos cannot carry this burden indefinitely.”