THESSALONIKI (AFP).- A fire during restoration works has caused serious damage to an historic 15th century Ottoman mosque in Didymoteicho, northeastern Greece, local officials said Wednesday.

"For the moment there is no indication that arson was involved," Nathanail Rigas, head firefighter of the Thrace region bordering Turkey, told AFP.

Rigas said restoration work could have sparked the fire at the Bayezid mosque. He added an investigation had begun and would rule nothing out.

The Greek ministry of culture lamented the damage to "a very important part of the country's cultural heritage" while underlining Athens' determination to complete restoration work begun last year with EU financial support.

Didymoteicho mayor Paraskevas Patsouridis said the mosque's ornate oak roof sustained "serious damage" from the fire, which broke out in the early hours and was tackled by more than 50 firefighters.

Patsouridis said no work had been going on at the site when the blaze started around 0100 GMT.

Greek police said a smaller fire had broken out on Tuesday -- reportedly during welding -- and had apparently been extinguished, but likely flared anew.

Initiated under Sultan Bayezid I and named after him, the mosque -- a cultural monument not in use for prayer -- is considered the largest in southeastern Europe and of unique architectural and historical importance.

The Turkish foreign ministry offered support to help preserve the site, a spokesman indicating they were first waiting for Greece to determine what had caused the fire.

"We are saddened to learn that Celebi Sultan Mehmet Mosque in Didymoteicho-Greece, built in 1420, and restoration of which was started in 2016 by the Greek authorities, was severely damaged as a result of a fire which broke out in the early hours of 22 March," a Turkish foreign ministry statement said.

The ministry added it was vital the mosque, "which is one of the most distinguished examples of our common cultural heritage with Greece," be restored and preserved for future generations.

The Greek region of Thrace has a Muslim minority of Turkish origin numbering around 100,000.


© Agence France-Presse