Indonesia's Mount Semeru has erupted, pouring ash an estimated 5.6km (3.4 miles) into the sky above Java, the country's most densely populated island.
No evacuation orders have so far been issued, and no casualties reported.
The National Disaster Mitigation Agency (NDMA) warned villagers living on the mountain's slopes to be alert for ongoing volcanic activity.
Footage showed ash from the 3,676m (12,060ft) volcano looming over homes.
"The villages of Sumber Mujur and Curah Koboan [in Lumajang municipality] are located in the trajectory of the hot clouds," local official Thoriqul Haq said on Saturday.
Residents of the Curah Kobokan river basin have been urged to watch for possible "cold lava" mudflow, which can be triggered by intense rainfall combining with volcanic material.
Mount Semeru erupted at about 17:24 local time (10:24 GMT), authorities said.
Indonesia sits on the Pacific "Ring of Fire" where tectonic plates collide, causing frequent volcanic activity as well as earthquakes.
Semeru - also known as "The Great Mountain" - is the highest volcano in Java and one of the most active. It is also one of Indonesia's most popular tourist hiking destinations.
The volcano previously erupted in December, when about 550 people were evacuated.