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.

Southern African heads of state re-affirmed their support for Democratic Republic of Congo in its fight against Rwanda-backed rebels who continue to take new territory in the east of the country.

Rwandan President Paul Kagame blasted criticism of his country's role in eastern Democratic Republic of Congo where rebels his government backs have seized its largest city, saying Kigali is prepared for "confrontation" if necessary.