Four people have died and two others have suffered severe burns while battling a wildfire on Indonesia's main island of Java, officials say.
The blaze erupted in recent days in the Semeru National Park in East Java's Probolinggo regency.
East Java police spokesperson Jules Abraham Abast said the victims were trying to contain the fire on Thursday, local time, as part of a 12-person crew.
Mr Abast said the team initiated an emergency call to colleagues outside the danger zone, saying they had become trapped by dense smoke and advancing flames about 1:30pm.
Rescuers later found three people dead and three others suffering severe burns at an evacuation point.
He said one of those suffering burns died while receiving treatment.
Smoke from Indonesia's wildfires continues to smother cities in the region like Medan in North Sumatra. (AP Photo/Binsar Bakkara)
Two volunteers remained hospitalised with serious burn injuries after being transferred to Dr. Soetomo General Hospital in Surabaya for specialised treatment, while six others escaped unharmed.
"The incident occurred in a remote mountainous area, complicating rescue efforts," said Probolinggo police chief Asmida Rizki Siregar.
She said authorities completed the evacuation late Thursday and had launched an investigation into the deaths, including whether negligence or criminal wrongdoing contributed to the tragedy.
The fire follows a major blaze in August that scorched nearly 9 square kilometres of grassland and vegetation, including protected edelweiss flowers, in the park.
Wildfires reignite haze concerns
The deaths came as Indonesia intensified efforts to combat forest and land fires that have worsened this year as El Niño intensifies a prolonged dry season.
Contributing factors also include land clearance using fire in the Indonesian part of Borneo and regions of Sumatra Island, as well as water shortages that have hampered Indonesian firefighters, who have received assistance from Japan.
Indonesia's Forestry Ministry recorded 799 hotspots nationwide as of Thursday evening, up sharply from 372 a day earlier.
More than three-quarters were concentrated in six fire-prone provinces on Sumatra and Borneo.
Toxic haze and smoke have caused a health crisis in neighbouring countries as well, including the Philippines.
The surge in fires has renewed concerns about trans-boundary haze across South-East Asia, with Malaysia ordering hundreds of schools to close in several states on Friday due to poor air quality.
Malaysian Foreign Minister Mohamad Hasan rejected calls to seek compensation from Indonesia, saying the crisis should be addressed through diplomatic engagement and Association of Southeast Asian Nations (ASEAN) mechanisms.
He said Malaysia was coordinating assistance for Indonesia and would push for stronger regional cooperation on haze management.
Singapore's Prime Minister Lawrence Wong said authorities were investigating companies allegedly linked to Indonesian forest and peatland fires that had worsened the haze and would pursue legal action where warranted.
Indonesia's Forestry Ministry recorded more than 2,020 square kilometres of burned land between January and July, almost three times Singapore's size.
The independent Nusantara Atlas project, which monitors fires using satellite imagery, estimated that nearly 8,960 square kilometres of land had burned by the end of August in Indonesia.
AP