As Rwanda-backed M23 rebels in eastern Democratic Republic of Congo push south towards the city of Bukavu, they are likely to have to fight their way through thousands of troops from Burundi, ramping up the risk of a return to full-blown regional war.

(Reuters) -Congolese troops with support from Burundi's army appeared on Friday to be holding back a push south by Rwandan-backed rebels seeking to expand their grip on eastern Congo in a weeks-old advance that has raised fears of a broader regional conflict.

Rebels in the Democratic Republic of Congo (DRC) have vowed to take their fight to the country's capital – but their attempts to march south are have been met by resistance.

U.S. Secretary of State Marco Rubio called for a urgent cease-fire in the conflict in eastern Democratic Republic of Congo saying Washington was "deeply troubled" by a recent escalation in the fighting.

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