Rwanda-backed rebels controlling cities in eastern Congo have forcibly closed settlement camps, leading to the displacement of more than 110,000 people in recent days, the U.N.

The march by Rwanda-backed rebels across eastern Congo risks escalating into a regional conflict, with countries such as Burundi, Uganda, and Tanzania already involved. Despite diplomatic efforts, tensions remain high.

Officials and residents say Rwanda-backed rebels have gained ground in eastern Congo despite the unilateral ceasefire they declared earlier this week, taking control of a town 100 kilometers (60 miles) from the provincial capital of Bukavu.

The Rwandan-backed M23 group on Friday advanced south after seizing the biggest city in mineral-rich eastern DR Congo, in violence that according to the United Nations has killed at least 700 people in less than a week.

Rwanda-backed rebels who have captured eastern Congo’s largest city say they plan to take their rebellion to the capital and seek to gain political power.