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.

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.

Forces of the Democratic Republic of Congo were losing control of the key city of Goma on Wednesday after rebel groups backed by Rwanda took over the airport and shared plans to set up a new administration.