NEW YORK (Thomson Reuters Foundation) - Thousands of refugees fleeing fighting between the army and armed groups in the central Democratic Republic of Congo have sought refuge in overcrowded villages across the border in Angola, the United Nations said on Friday.

More than 11,000 refugees have fled Kasai-Central province amid clashes between local militias and Congolese forces that started last August, with some 9,000 arriving since the start of this month, the U.N. refugee agency (UNHCR) said.

Refugees, about half of whom are children, are arriving in Angola in desperate conditions, many of them malnourished, sick and fearful for their lives amid reports of civilians being targeted, UNHCR said.

“Refugees are arriving in desperate conditions, without access to clean water, food or shelter,” the agency’s spokesman, Babar Baloch, told reporters in Geneva.

Refugees reported fleeing attacks from militia groups, who are targeting police, military officials and civilians who they believe are supporting or representing the government, Baloch said.

Some of the refugees have had to hide in the forest for days in their bid to reach safety in Angola, Congo’s southern neighbor, UNHCR said.

The latest violence in the central African country, a tinder box of conflicts over land, ethnicity and minerals, has worsened since security forces killed the leader of the Kamuina Nsapu militia.

The killing has sparked a rebellion against security forces in the impoverished Kasai region.

Fighting in Kasai has resulted in more than 400 deaths and displaced more than one million, with the United Nations identifying 40 mass graves.

Angolan authorities said on Wednesday they were reinforcing security patrols along the border with Congo in order to keep the militias from infiltrating their territory, local media reported.

The refugees would be treated humanely, police chief Ambrósio de Lemos was quoted as saying.

For those still caught between warring parties, the suffering endured by children was particularly worrying, the U.N.’s children (UNICEF) agency said.

Some 2,000 children in Kasai had been enrolled by the militias as child soldiers and another 300 had been seriously injured, it said.

“They should be safe in their homes ... not forced to fight on the battle field and killed or injured in violence,” UNICEF representative Tajudeen Oyewale told reporters.

Late last month, the United Nations renewed its peacekeeping mission in the country, which currently counts nearly 17,000 soldiers deployed on the ground.

Still, analysts fear growing violence could spark a repeat of the conflicts between 1996-2003, mostly in the east, in which millions died, mainly from hunger and disease.

President Joseph Kabila’s failure to step down when his two-term mandate expired in December has further destabilized the loosely governed country.