Congo's leader has called on young people to enlist in the army to help fight Rwanda-backed rebels attempting to seize more territory in the country's conflict-battered east.

As an East African bloc urged an immediate ceasefire in eastern Democratic Republic of Congo, Rwandan-backed M23 rebels who seized the city of Goma extended their advance on Wednesday, and Congo said it planned a campaign to recover lost territory.

Regional tensions spiral as peacekeepers killed in fighting following Rwandan-backed M23 rebel group offensive

Local sources said Kigali-backed fighters were advancing on a new front and had seized two districts in South Kivu province, after the rebel group’s capture of most of Goma, the capital of North Kivu.

South African President Cyril Ramaphosa accuses Rwanda of backing M23 rebels behind escalating crisis in eastern Democratic Republic of Congo this week

The rebels, which Rwanda denies supporting, have long been funded at least in part by the illicit mineral trade.

Many Congolese see the rebel advance as an invasion of their country by a foreign power in an attempt to seize land and Congo’s valuable rare minerals.

The Rwanda-backed armed group M23 vowed Thursday to "continue the march of liberation" to the DR Congo capital Kinshasa, as its fighters made further advances in the mineral-rich east of the country.

Reuters quoted the spokesperson as saying that the UN is deeply concerned by these developments, which are backed by "credible reports."

Democratic Republic of Congo President Felix Tshisekedi has vowed “a vigorous and coordinated response” against a rebel alliance that has besieged swaths of the nation’s mineral-rich east and forced hundreds of local troops and foreign mercenaries to surrender.

President Paul Kagame said Rwanda was ready for "confrontation" as he rejected criticism over his backing for M23 rebels who were pushing south on Thursday in eastern Democratic Republic of Congo after capturing the major city of Goma.