Eko described the presence of unofficial routes as the biggest challenge for authorities, saying they “effectively paralyse the monitoring system”.
A receptionist at a hotel in Tobelo, the closest town to Mount Dukono, told CNA on Friday that there are two access routes to the volcano – an official hiking trail and an unmonitored alternative route that was frequently used by tourists despite the eruptions.
A local tour guide, citing fellow guides, said that the victims had taken a faster but more dangerous route up Mount Dukono, although it remains unclear whether the path was unofficial.
“Authorities have no data on who is on the mountain, how many people are there, and where hikers are located when the danger escalates,” Eko said, referring to hikers using unofficial routes.
Such a situation also directly affects search and rescue operations, making them more difficult, costly and risky, he added.
Singapore’s Ministry of Foreign Affairs and embassy in Jakarta were working with the Indonesian authorities to gather information and provide consular assistance and support to the affected Singaporeans and their families, the ministry said in a statement on Friday.
The volcanology agency is maintaining the third-highest alert level for Mount Dukono, said Lana Saria, the agency’s head, adding that residents and tourists were advised not to do any activities within 4km of the crater.
There were no reports of flight disruptions caused by the eruption.
Indonesia sits on the Pacific “Ring of Fire”, an area of high seismic activity atop various tectonic plates.