Volcanic ash that has fallen like heavy rain onto a 9th-century temple complex is threatening one of Indonesia's most popular tourist attractions, officials said Friday.
Parts of the famed Borobudur temples have been closed to the public so workers can clean off the blanket of white ash from Mount Merapi, which began erupting Tuesday.
Antiquities experts are concerned the acidic soot will speed the decay of the stones, said Marsis Sutopo, head of the temple conservation office.
Visitors can still enter the outside yard to the temples but won't be able to go inside the gates until at least next week, officials said. A Mahakarya Borobudur traditional dance performance will go on as scheduled Saturday.
The Borobudur temples drawing millions of visited every year. Built by Javanese rulers in the 9th-century, they are reminders of the rich Hindu and Buddhist past of what is now the world's most populous Muslim nation.
The temple complex was abandoned for centuries — the reasons remain a mystery — and lay hidden under layers of volcanic ash and jungle growth until it was discovered in 1814 by Sir Thomas Stamford Raffles during the English occupation of Java island, the cultural and population center of modern-day Indonesia.
UNESCO guided and financed a massive restoration in the 1970s.