Papua New Guinea's volatile Ulawun volcano began spewing ash on Wednesday, prompting authorities to evacuate villages near the area.
The volcano on the remote Bismarck Archipelago chain is listed as one of 16 'Decade Volcanoes' targeted for research.
"The volcanic activity at Mt Ulawun began at 7:00 am this morning (local time) after slight rumbling and light emission," an official with the West New Britain Disaster Office observed.
"The Rabaul Volcano Observatory has declared a stage one alert warning of a possible eruption."
Witnesses reported ash spewing out of the summit, turning the sky dark.

Family of alleged Bondi gunman unaware of 'radical mindset', say Indian police
Israeli forces kill Palestinian teen in West Bank, health ministry says
Trump sues BBC for defamation, seeks up to $10 billion in damages
FBI foils 'terror plot' targeting Los Angeles
