Almost one million people have fled their homes in eastern Democratic Republic of Congo so far this year, the International Organization for Migration (IOM) said on Thursday.
"A surge in attacks on civilians by non-state armed groups has newly displaced close to one million people in the Democratic Republic of the Congo (DRC) since January," the IOM said in a statement.
In total an estimated 6.1 million people are internally displaced in the DRC, a 17 percent increase from October 2022, it added.
"As the conflict intensifies, the humanitarian situation continues to deteriorate, and millions are facing acute food insecurity as well as other critical needs," the UN agency said.
Since the beginning of the year armed attacks against civilians in the eastern Kivu and Ituri regions have resulted in loss of life, massive population displacements and growing instability, the organisation stressed.
"Across the country, over 26 million people need humanitarian aid" from a population of around 100 million, the IOM said.
In the early hours of Monday, at least 46 people, half of them children, were killed in a militia attack on a camp for displaced people in Ituri province, security analysts and a local community leader said.
That attack was blamed on the CODECO militia, or Cooperative for the Development of the Congo, which claims to protect the Lendu community from rival ethnic group, the Hema.
This tragedy also "resulted in the renewed displacement of over 7,800 people from the site, destruction of shelter and personal belongings," the IOM said.
"IOM strongly condemns this heinous violation of international humanitarian law and recalls that attacks against civilians may constitute war crimes," it added.
On Thursday the International Criminal Court in The Hague announced it will examine allegations of war crimes by armed groups in the Democratic Republic of Congo's volatile east, after Kinshasa made a new formal referral to the tribunal.
Kinshasa has accused the M23 rebel group of attacks in the DRC's mineral-rich North Kivu province, and says Rwanda is backing the Tutsi-led militia. Kigali denies any involvement in the violence.
The DRC referred the situation to the Hague-based ICC in 2004, but has now made a second referral asking that it launch an investigation into the latest alleged crimes, ICC prosecutor Karim Khan said.
Armed groups have plagued much of the eastern DRC for three decades, a legacy of regional wars that flared in the 1990s and 2000s.