An Indonesian guide who led a group of hikers up Mount Dukono has described the harrowing moment they were caught in Friday's eruption, which killed three people.
Reza Selang narrowly escaped being crushed by a large rock ejected from the crater that landed on two other hikers beside him.
"There are no words. Until now I still feel torn apart," he told the BBC.
The group of 20 hikers, a mix of Singaporeans and Indonesians, had climbed to the summit despite warnings. The volcano has erupted more than 200 times since late March, and authorities had banned climbing permits since 17 April. Reza said he was unaware of the prohibition.
Last Thursday, the group began hiking with no signs of activity. The next morning, 14 hikers approached the crater. At 07:40 local time, the mountain erupted twice in quick succession.
Reza spotted a hiker, Shahin Muhrez bin Abdul Hamid, lying on the ground. He and Singaporean organizer Timothy Heng attempted a rescue. A 2-meter-wide rock bounced towards them, crushing Heng and Shahin instantly.
Reza alerted authorities, who retrieved the bodies over the weekend. Authorities have permanently closed Mount Dukono and are investigating possible negligence. Reza has been questioned by police.
"I feel very guilty toward the victims and their families," Reza said. "I want to kneel at the victims' parents' feet."