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.

Rwandan-backed M23 rebels have entered Bukavu, the second-largest city in the eastern Democratic Republic of Congo, seizing the regional governor's office. Some people lined the streets to clap and cheer the fighters as they marched and drove into the city centre without resistance.