JAKARTA, Indonesia — A fire destroyed 60 hectares (148 acres) of land in the Mount Bromo area in a national park in Java, Indonesia’s most populous island, since Monday, officials said on Thursday.

The burning area, equivalent to more than 80 soccer fields, is located within the Bromo Tengger Semeru National Park, one of the most popular tourist destinations in East Java Province.

The National Disaster Management Agency in a written statement said that the terrain has posed a significant challenge to firefighting efforts. Local authorities have not yet determined the cause of the fire.

“A number of hot spots are located on the slopes of Bromo, which are steep and difficult for ground-based firefighters to reach. In addition, strong winds in the area have the potential to accelerate the spread of the fire,” Abdul Muhari, the agency’s spokesperson, said in the statement Thursday.

He added that the agency deployed two water-bombing helicopters on Thursday to help extinguish hotspots located on steep slopes that are difficult for ground teams to reach.

The agency is also preparing weather modification operations such as cloud seeding as an additional measure.

Indonesian authorities also closed part of the Mount Bromo tourist area until further notice as a safety measure.

Forest fires have also been reported at several locations on the islands of Sumatra and Borneo since the beginning of the month.

One person died after running out of oxygen while trying to escape through the smoke from the forest fire in Ketapang Regency in West Kalimantan Province, according to Ketapang Disaster Management Agency.

Forest fires on Sumatra and Borneo islands often break out during dry spells, smothering parts of nearby Singapore and Malaysia in haze.

__ Associated Press journalist Niniek Karmini in Jakarta, Indonesia, contributed to this report.