LONDON — At least 15 people were killed after a volcano in the eastern Democratic Republic of the Congo erupted on Saturday night for the first time in almost two decades, officials said.

Mount Nyiragongo, located in the mountains of Virunga National Park, spewed red fumes into the night sky and sent a scorching river of lava downhill toward Goma, a lakeside city of 2 million people less than 10 miles away.

The Congolese government ordered residents of Goma to evacuate as fiery lava engulfed hundreds of homes and other buildings along the city’s outskirts. Panicked residents began fleeing, many on foot, hours before the official evacuation notice.

The lava crossed a major highway connecting Goma with the city of Beni, severing a key supply route, but ultimately stopped short of Goma’s city limits.

Nine people were killed in car accidents while trying to evacuate, while another two people were burned to death. Four inmates at Munzenze prison in Goma also died while trying to escape during the volcanic eruption, according to Congolese government spokesperson Patrick Muyaya. The death toll could rise in the coming days as officials inspect the trail of destruction.

Damage was reported in at least 17 villages surrounding the volcano, including suburbs of Goma. In addition to many homes, the lava destroyed several health centers, a primary school, a water pipeline and Goma’s main electricity supply line, Muyaya said.

At least 25,000 people were internally displaced on Sunday and more than 150 children were separated from their families. Over 170 children are also feared to be missing, according to the United Nations International Children’s Emergency Fund (UNICEF).

Meanwhile, some 8,000 people crossed the country’s border into Rwanda to seek refuge following the eruption, according to the Rwandan Ministry in Charge of Emergency Management, which said most people were returning home Sunday morning after the lava flow had stopped.

Muyaya confirmed later Sunday that those who fled are gradually starting to return to their homes, or least what is left of them. While it was unclear exactly how many households were impacted by the eruption, UNICEF said it is concerned about people returning to find destroyed or damaged homes and a lack of electricity or water.

Local authorities reported several seismic tremors in Goma on Sunday afternoon, according to Muyaya, who urged residents to remain calm and vigilant.

Congolese President Felix Tshisekedi decided to cut short his trip to Europe and return home on Sunday so he could oversee the coordination of aid to the affected areas, his office announced via Twitter.

Mount Nyiragongo, one of the most active and dangerous volcanoes in the world, last erupted in 2002, killing hundreds of people and leaving more than 100,000 homeless.