The government in the Democratic Republic of Congo has launched an evacuation plan for the eastern city of Goma after a large volcano erupted.
Mount Nyiragongo is throwing huge lava fountains into the air, red fumes spewing into the night sky.
Panicked residents of Goma – population two million – are fleeing to safety.
The volcano, located about 10km (six miles) from the city, last erupted in 2002, killing 250 people and making 120,000 homeless.
“The evacuation plan for the city of Goma has been activated. The government is discussing urgent measures to take now,” a government spokesman tweeted.
Earlier on Saturday resident Carine Mbala told AFP news agency: “There is a smell of sulphur. In the distance you can see giant flames coming out of the mountain.”
Before announcing the evacuation plan, government spokesman Patrick Muyaya said the government was “closely monitoring” the situation, urging the population to stay calm.
People have been advised to evacuate towards the town of Sake.
A video posted to Twitter by The New Times in Rwanda showed the eruption from the town of Rubavu, near the border with Rwanda.
Others have been posting videos of lava spewing out of the volcano, which recorded its deadliest eruption in 1977, when more than 600 people died.
The Goma Volcano Observatory has been struggling to monitor Mount Nyiragongo since the World Bank cut funding amid allegations of corruption.