By Yassin Kombi and David Lewis GOMA, Democratic Republic of Congo (Reuters) -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,

Advances being made by the M23 rebel group in the Democratic Republic of Congo are "heightening the threat of a regional war," according to U.N. Secretary General Antonio Guterres.

Angolan President Joao Lourenco has urged warring parties in the Democratic Republic of Congo (DRC) to return to peace talks, which collapsed last year, the foreign ministry said.

Angola’s President Joao Lourenco demanded the immediate withdrawal of Rwandan troops from Congolese territory on Wednesday amid fighting with the M23 rebels in Goma. Lourenco, who is the African Union (AU) mediator between Congo and Rwanda, also urged the resumption of peace talks with the M23 and all other groups operating on Congolese territory.

M23 rebels have made rapid advances in the latest bout of conflict that has long-dogged the mineral-rich east.

President Paul Kagame says Rwanda was ready for 'confrontation' as he rejected criticism over his backing for M23 rebels who were pushing south in eastern Democratic Republic of Congo

The latest fighting has heightened an already dire humanitarian crisis in the region, forcing half a million people from their homes since the start of the year.

A conflict that has raged for decades reached a flashpoint this week when rebels backed by Rwanda marched on a key Congolese city in a bid to occupy territory and exploit minerals.

Rwanda-backed rebels who have captured eastern Congo’s largest city say they plan to take their rebellion to the capital of Kinshasa and seek to gain political power.

Dead bodies lie on the streets of Goma in the eastern Democratic Republic of the Congo, as heavy fighting continues between Rwanda-backed M23 rebels, and the DRC forces supported by international peacekeeping troops.

The conflict comes amid rising global tensions after Donald Trump’s election, especially between Washington and Beijing, over control of strategic minerals like those present in the Congo.

Rwanda-backed fighters were in control of almost all of the DR Congo city of Goma Wednesday where residents were re-emerging after days of deadly fighting and Angola urged leaders of