The U.N.'s top human rights body was holding an urgent session on Friday on spiralling violence in eastern Congo, where Rwanda-backed rebels recently captured a key city and some 3,000 people have been killed and nearly as many injured since late January.

Rwanda-backed rebels were quickly expanding their presence in eastern Congo after capturing Goma, the region's major city, the U.N. said Friday, also expressing concerns over executions it learned were carried out by the rebels following a major escalation of their yearslong rebellion.

Goma remains “under occupation” by Congo’s M23 rebels and the ceasefire they announced has been broken as their forces engage in heavy fighting along the main route to South Kivu’s main city Bukavu.