TOKYO (AP) — A fire has spread among structures at Shuri Castle on Japan's southern island of Okinawa, nearly destroying the UNESCO World Heritage site.

Firefighters were still battling the blaze a few hours after the fire started early Thursday and nearby residents were evacuated to safer areas, Okinawa police spokesman Ryo Kochi said.

The fire in Naha, the prefectural capital of Okinawa, started from the castle's main structure. The main Seiden temple and a Hokuden structure, or north temple, have burned down. A third structure Nanden, or south temple, is nearly destroyed, Kochi said.

Nobody has been injured. The cause of the fire was not immediately known.

Footage on NHK television showed the castle engulfed in orange flames.

The ancient castle is a symbol of Okinawa's cultural heritage from the time of Ryukyu Kingdom that spanned about 450 years from 1429 until 1879 when the island was annexed by Japan.

The castle is also a symbol of Okinawa's struggle and effort to recover from World War II. Shuri Castle burned down in 1945 during the Battle of Okinawa near the war's end, in which about 200,000 lives were lost on the island, many of them civilians.

The castle was largely restored in 1992 as a national park and was designated as the UNESCO World Heritage site in 2000.

Okinawa was under the U.S. occupation until 1972, two decades after the rest of Japan regained full independence.

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