GOMA: The risk of further eruptions from volcano Nyiragongo led DR Congo authorities to order the evacuation of parts of the city of Goma Thursday, causing an immediate exodus of tens of thousands of people.

"Current data on seismicity and the deformation of the ground indicate the presence of magma under the urban area of Goma, with an extension under Lake Kivu," the local military governor General Constant Ndima said in a broadcast public address.

"Right now we can't rule out an eruption on land or under the lake, which could happen very soon and without warning," he added."The situation can change rapidly, and is being constantly monitored."

Ndima said there were also supplementary risks associated with the interaction between magma and water in Lake Kivu.

There were several potential problems linked to this, he explained, among them the "destabilisation of the volume of gas dissolved in Lake Kivu and the emission of potentially dangerous gases at the surface".

He said evacuation is necessary and should be done calmly and without rushing.

Authorities have arranged transport towards Sake, around 20 kilometres (12 miles) west of Goma, in each of the ten districts of the city affected, Ndima said.

"People should take the bare minimum with them, to make sure everyone has a chance to get on," he added.