Torrents of lava poured into villages after dark in eastern Congo with little warning, leaving at least 15 people dead and destroying more than 500 homes, officials and survivors said.

The eruption of Mount Nyiragongo on Saturday night sent about 5,000 people fleeing from the city of Goma across the nearby border into Rwanda, while another 25,000 sought refuge to the north west in Sake, the UN children’s agency said.

More than 170 children were still feared missing on Sunday and Unicef officials said they were organising transit centres to help unaccompanied children.

Goma was largely spared the mass destruction it suffered the last time the volcano erupted in 2002. Hundreds died then and more than 100,000 were left homeless.

On Sunday, Aline Bichikwebo and her baby escaped when the lava flow reached her village, but her mother and father were among those who died. Community members gave a provisional toll of 10 dead in Bugamba alone, though provincial authorities said it was too soon to know how many were killed.

Ms Bichikwebo said she tried to rescue her father but was not strong enough to move him to safety before the family’s home was ignited by lava.

“I am asking for help because everything we had is gone,” she said, clutching her baby. “We don’t even have a pot. We are now orphans and we have nothing.”

The air remained thick with smoke because of how many homes had caught fire when the lava came.

“People are still panicking and are hungry,” resident Alumba Sutoye said. “They don’t even know where they are going to spend the night.”

Authorities said at least five people died in a truck crash as they were trying to evacuate Goma, but the scale of the loss has yet to be determined in some of the hardest-hit communities.

Residents said there was little warning before the dark sky turned a fiery red, sending people running for their lives in all directions. One woman went into labour and gave birth while fleeing to Rwanda, the national broadcaster there said.

Smoke rose from smouldering heaps of lava in the Buhene area near the city on Sunday.

“We have seen the loss of almost an entire neighbourhood,” Innocent Bahala Shamavu said. “All the houses in Buhene neighbourhood were burned and that’s why we are asking all the provincial authorities and authorities at the national level as well as all the partners, all the people of good faith in the world, to come to the aid of this population.”

Witnesses said lava engulfed one highway connecting Goma with the city of Beni, but the airport appeared to be spared the same fate as 2002 when lava flowed on to the runways.

Goma is a regional hub for many humanitarian agencies in the region, as well as the UN peacekeeping mission.

While the city is home to many UN peacekeepers and aid workers, much of surrounding eastern Congo is under threat from armed groups vying for control of the region’s mineral resources.