As Rwanda-backed rebels strolled through the streets of eastern Democratic Republic of Congo's second-largest city, President Felix Tshisekedi's office claimed it was actually still controlled by his army and "valiant" allied forces.

DAKAR, Senegal — Rwanda-backed rebels appeared to be heading toward a third major city in eastern Congo, residents said Tuesday, as international pressure rose over the M23's expansion in a mineral-rich region that’s critical for global technology.

The UN's human rights chief accuses Rwanda-backed M23 rebels of killing children and attacking hospitals in eastern Congo. M23, having seized cities Bukavu and Goma, is accused of seeking control over Congo's mineral-rich region with Rwanda's support.