Indonesia's Lewotobi Laki-Laki volcano erupted on Saturday for the second day in a row, spewing ash up to 18 kilometers (11.2 miles) from its summit, according to the Center for Volcanology and Geological Hazard Mitigation.
The ash column reached more than 19.5 kilometers (12.1 miles) above sea level, the agency said.
The center also warned of potential cold lava floods from the volcano, following the recent eruptions, state-run news agency Antara reported.
There were no immediate reports of casualties.
Authorities urged residents and tourists to stay at least six to seven kilometers — 3.7 to 4.3 miles — away from the volcano.
At least nine people were killed and dozens injured after an eruption at the same volcano in November.
The 1,584-meter (5,197-foot) peak is part of a twin volcanic system with Mount Lewotobi Perempuan in Flores Timur district.
Indonesia has 120 active volcanoes and sits along the Ring of Fire, a seismic belt of fault lines encircling the Pacific Basin.
Separately, the National Disaster Mitigation Agency said on Saturday that it was monitoring several fire hotspots in West Kalimantan province, near the Malaysian border.
Authorities are tracking the affected areas by satellite and with air task force patrols, the agency said. As of Thursday, the fires had spread across 1,149 hectares.
