NEW YORK, 12th December, 2025 (WAM) -- More than half a million people have now been uprooted by escalating violence in eastern Democratic Republic of the Congo (DRC), the UN said on Thursday, warning that the M23 rebel offensive is driving a rapidly worsening humanitarian emergency.

The UN's Deputy Spokesperson said Secretary-General Antonio Guterres was "deeply alarmed" by the surge in attacks across South Kivu, where what's officially known as the Alliance Fleuve Congo/Mouvement du 23 mars (AFC/M23) has advanced into several towns since 2 December.

The UN and Security Council have repeatedly described the majority-Tutsi M23 militia as backed by Rwanda but Kigali has consistently denied providing support.

"The Secretary-General underscored that this escalation risks seriously undermining efforts to achieve a sustainable resolution of the crisis and increases the risk of a broader regional conflagration," Farhan Haq said in a statement.

Dozens of civilian deaths and many more injuries have also been reported in Kamanyola, Luvungi, Katogota and Uvira triggered mass displacement and caused civilian casualties.

Guterres called for an "immediate and unconditional cessation of hostilities," urging all parties to honour commitments made under the peace accords signed by the leaders of DRC and Rwanda in Washington on 4 December and the Doha Framework Agreement reached in November.

He added the UN remains "fully mobilised" to support lifesaving assistance and ongoing diplomacy, stressing that "the risk of regional conflagration is real, and the need for de-escalation is urgent."

The UN aid coordination office (OCHA) said new assessments indicate that more than 500,000 people have been displaced in just over a week, a dramatic rise from earlier estimates.

While some families have returned to areas where fighting has momentarily subsided, most remain in overcrowded sites where the risk of cholera, mpox and other disease outbreaks is rapidly rising.

In the key town of Uvira - reportedly overrun by AFC/M23 fighters on Wednesday - the situation was described as relatively calm on Thursday, though sporadic gunfire continued in several neighbourhoods.

Radio Okapi, operated by the UN peacekeeping mission MONUSCO, reported that the city's streets were deserted, the border crossing with Burundi closed, and residents sheltering indoors amid fear and uncertainty.