Thousands of displaced residents at an Ebola-hit camp in eastern Democratic Republic of Congo have fled after soldiers entered the site, UN and Congolese officials said on Thursday, raising concern about the disease's spread.

Security forces went to the Kigonze camp looking for weapons and clashes ensued, causing camp residents to flee over the last week, according to Congolese and health officials.

The camp for some 19,000 displaced residents in Ituri province now lies abandoned, UN Senior Ebola Coordinator Julien Harneis said in a statement.

Two health officials with knowledge of the situation said that about 1,000 Ebola contacts were resident in the camp. Only about a fifth of those have since been traced, one of the sources added.

‘Enormous challenge’

"The enormous challenge of halting the spread of Ebola in the Democratic Republic of the Congo (DRC) just became even harder...," the UN said.

It said an Ebola transit centre where suspected Ebola cases could be isolated, tested and treated was also burned down.

The UN refugee agency told Reuters there have been 88 confirmed Ebola cases in Congo displacement sites and 56 deaths, including those in Kigonze. The toll was likely an underestimate, it said.

Ebola often spreads quickly in displacement camps where aid groups say overcrowding and poor sanitary conditions are common.

Ituri is the worst affected province of the current outbreak, which was declared in May. It is already the deadliest outbreak in Congo's history, having killed at least 3,982 people.