Nearly 400 tourists were evacuated in Indonesia on Wednesday after Mount Barujani erupted on Lombok island, one of the country's most popular hiking destinations.
Mount Barujani, a smaller cone within the crater of Mount Rinjani, sent columns of ash and smoke shooting 2 km into the sky late on Tuesday afternoon.
National disaster agency spokesman Sutopo Purwo Nugroho said nearly 400 people were hiking near Barujani when the volcano started erupting. The authorities decided to evacuate the place immediately.
"A rescue team has been sent to Mount Rinjani to evacuate the tourists. They set off on Wednesday morning," Nugroho told AFP.
The officials urged the hikers to maintain a distance of at least 3 km from the smouldering volcano which is a key attraction on the multi-day trek to the summit of Mount Rinjani. Every year, thousands of tourists come for trekking here.
Nugroho said since Sunday 389 hikers were recorded as having entered the national park. He also said the overwhelming majority of those hikers were foreigners.
The spokesperson also added that rescue teams suspected some hikers may have gone off-piste avoiding the official route to the summit.
Although the authorities upgraded the threat level of the volcano on Tuesday as Barujani sent plumes of smoke and hot ash into the atmosphere, it still remains two steps from the highest-risk category.
Transport ministry spokesman Hemi Pramuraharjo said there were no flight disturbances on Wednesday due to the ash clouds.
Several flights to and from the nearby resort island of Bali were cancelled overnight but the international airport at Lombak was not affected.
Volcanoes and flight disruptions are not uncommon in Indonesia. The archipelago of 250 million people is prone to earthquakes and volcanoes because it sits on a belt of seismic activity known as the Pacific Ring of Fire, a string of faults that lines the Pacific Ocean.
The Pacific Ring of Fire is a home to almost 130 active volcanoes.
In August, an eruption at Mount Rinjani forced the closure of Lombok airport and disrupted many flights to neighbouring Bali.