In DR Congo, Mount Nyiragongo turned the sky red and spewed out a river of lava on Saturday, but stopped short of Goma, a city of two million just south of the volcano.
At least 15 deaths have been confirmed, but the number is likely to rise as officials reach the hardest-hit areas. Nine of the victims died in a traffic accident as people fled.
Four others were killed as they tried to escape a prison while two were burned to death, government spokesman Patrick Muyaya said on Sunday.
According to Unicef, more than 170 children are feared to be missing and 150 others had been separated from their families; centres would be set up to help unaccompanied minors, said Unicef.
The volcano, located 10km (six miles) from Goma, last erupted in 2002, killing 250 people and making 120,000 homeless.
People in the Democratic Republic of Congo are returning to scenes of devastation after a large volcano erupted.
Patrick Muyay, Communications Minister said seismic tremors had been felt in the area in the aftermath and advised people to remain vigilant, avoid non-essential travel, and follow directions .
Overnight, many residents headed across the nearby Rwandan border, while others went to higher ground to the west of the city.
Rwandan authorities said about 3,000 people had officially crossed from Goma. The country’s state media said they would be accommodated in schools and places of worship.
Mount Nyiragongo is one of the world’s more active volcanoes but there were concerns that its activity had not been properly observed by the Goma Volcano Observatory, since the World Bank cut funding amid allegations of corruption.
Professor Mike Burton, a volcanologist at the University of Manchester in England, told the BBC the lava in Mount Nyiragongo is particularly fluid and has the potential to move fast.
In a report on 10 May, the observatory warned that seismic activity at Nyiragongo had increased.
Last year, the observatory’s director, Katcho Karume, told the BBC World Service’s Science in Action that the volcano’s lava lake had been filling up quickly, increasing the chances of an eruption in the next few years. But he also warned that an earthquake could trigger a disaster earlier.
The deadliest eruption of the volcano was in 1977, when more than 600 people died.