A helicopter belonging to the National Search and Rescue Agency (Basarnas) crashed in Temanggung, Central Java, on Sunday afternoon, killing eight people on board.
The helicopter was on a rescue mission to the Dieng Plateau in Central Java where an active volcanic crater and famous tourist destination, Sileri Crater, erupted at 12 p.m. It was spurting cold lava and sending smoke 50 meters in the air.
The helicopter departed from the Central Java's provincial capital of Semarang at 4 p.m.
Basarnas operational director Maj. Gen. Heronimus Guru confirmed there were eight people on board the ill-fated helicopter, consisting of four crew and four rescuers.
Central Java Basarnas spokesman Zulhawary Agustianto told The Jakarta Post they predicted the helicopter hit a cliff in an area called Canggal in Candiroto district.
Central Java Police chief Insp. Gen. Condro Kirono said joint 100 joint personnel had reached the crash site.
At least 17 tourists were at the crater when the eruption occurred, according to the National Disaster Mitigation Agency (BNPB).
Ten of them who sustained injuries, which ranged from bruises to a fractured arm, were immediately brought to a nearby community health centre to receive treatment.
"The authorities asked visitors and residents to vacate the area because there was potential for the crater to erupt for a second time," BNPB spokesman Sutopo Purwo Nugroho said in a statement.
The phreatic eruption was caused by gas pressure under the ground, resulting in an explosion that sent out a mix of steam, water, ash and mud, Sutopo added.
According to the local disaster agency, Sileri Crater is the most active and dangerous crater in the volcanic Dieng Plateau, with six eruptions recorded from 1939 to 2009.
"We were all panicking at the time. The eruption produced a lot of smoke and mud. It was terrifying," said Amin Abdurrahmah, a 17-yearold tourist from Banyumas who visited the site that day.