Around 400,000 people have fled the city of Goma and its surroundings in the Democratic Republic of the Congo (DRC), as the threat of another volcanic eruption at Mount Nyiragongo looms, a provincial government spokesperson said Friday.

Iran Press/Africa: The spokesperson for the military governor of North Kivu, said that the Volcanic Observatory of Goma had identified magma under the city that also extends under Lake Kivu. While that magma has partially drained, radar images indicate that the crater inside the summit of the volcano continues to expand, he reported.

"On the basis of this information, we still can't exclude a ground eruption or an eruption under the lake -- but one could come with very little or no warning," the spokesperson said. The 11,500-foot-high volcano first erupted last Saturday, killing at least 31 people.

Since then, the area has experienced a series of earthquakes and tremors, some felt as far away as the Rwandan capital of Kigali, 65 miles from the volcano in the Virunga National Park.

Ten neighborhoods in the "red zone" area of the city of Goma are now being evacuated due to risks, with significant cracks in the ground -- some stretching the entire width of the road, others in the walls of buildings -- already visible. Around 80,000 households have been evacuated so far, the spokesperson said.

Many of those fleeing have traveled on foot, carrying mattresses and cooking utensils, the United Nations Children's Emergency Fund (UNICEF) said Thursday.

The military spokesperson said that displaced people had been arriving at evacuation zones that would facilitate assistance from the government and humanitarian organizations.

Earlier Friday, UNICEF warned that up to 400,000 people, including nearly 280,000 children, could be displaced if the volcano erupts again.

Goma, the capital of North Kivu province, is situated at the edge of Lake Kivu on the DRC's border with Rwanda. According to official projections from the UN, World Bank, and others, the city is home to approximately 670,000 people -- however, a number of non-governmental organizations in the region place the population closer to 1 million.