FILE PHOTO: General view shows the Moria camp for refugees and migrants on the island of Lesbos, Greece, December 1, 2017. REUTERS/Alkis Konstantinidis/File Photo

ATHENS (Reuters) - A 26-year old Syrian man set himself on fire at a refugee camp on the Greek island of Lesbos on Thursday, in one of the most serious incidents involving stranded migrants in many months.

The man was slightly burned and was treated at a local hospital, an official said. Local media said the incident took place outside an asylum office at Moria camp, which is a former military base set on a hilltop. Conditions there are poor.

At least 5,000 refugees and migrants are living in Moria and another camp on the island, more than their 3,000 capacity, awaiting for months for word on their future.

More than 60,000 refugees and migrants, most from Syria, Iraq and Afghanistan, have been in Greece for more than a year after border shutdowns throughout the Balkans halted the onward journey many planned to take to central and western Europe.

Lesbos was the main gateway to Europe in 2015 for nearly a million refugees and migrants and this month marks two years since the European Union and Turkey agreed to stem the flow.

Under the deal, migrants arriving n Greek islands must be returned to Turkey unless they qualify for asylum but processing papers can take months and protests over delays are common.

About a dozen asylum seekers were treated after clashes with police in Moria and about 200 women and children were evacuated to a nearby warehouse last week.