An outbreak of fighting in the eastern Congolese province of South Kivu has forced more than 35,000 civilians to flee their homes in the past two weeks.

The latest population movement brings the total number of civilians to have been displaced in South Kivu since January as a result of clashes between government forces and Rwandan rebels, and reprisal attacks on civilians, to about 536,000 people.

"We are gravely concerned that the renewed fighting in South Kivu will have a negative impact on UNHCR-organized voluntary repatriation of Congolese refugees from neighbouring Tanzania, the majority of whom are from the province," a UNHCR spokesman said on Friday.

Initial UNHCR estimates show that at least 35,000 people have been displaced in the Ruzizi River plain, where the Democratic Republic of the Congo borders Rwanda and Burundi. These people reportedly fled iafter the government launched a fresh military campaign on July 12 in the Uvira area of South Kivu. The campaign is aimed at the disarmament of the so-called Democratic Forces for the Liberation of Rwanda (FDLR) and their local militia allies.

Many of the residents of Lemera and Mulenge, two of the major towns in the region north of Uvira, are reported to have fled and an estimated 19,000 people are said to be hiding in the forests and villages near Lemera.

The majority of the displaced civilians are seeking protection with host families in areas where it is still safe, while others have sheltered in schools, churches and other public buildings. Internally displaced people (IDPs) in the conflict areas in the mountains of the Moyens Plateaux remain almost completely inaccessible.

There are widespread reports from IDPs of atrocities, including accusations of murder, rape and torture on the part of FDLR rebels. Fleeing populations also report arbitrary arrests, kidnappings, extortion and forced taxation by the FDLR and various armed groups backing the Rwandan Hutu rebels.

Due to lack of access and insecurity it is extremely difficult to assess the scope of the latest displacement. So far, UNHCR has tentatively pre-registered some 20,000 individuals in the Luberizi-Kamanyola axis, along the Burundi border, where most of the new IDPs had gathered.

The UNHCR office in the South Kivu lakeside town of Bukavu reports that families continued to be on the run throughout the week. Preliminary evaluations conducted in coordination with other humanitarian partners show that these people need food, water, medical supplies and basic aid items such as blankets, mattresses and cooking utensils.

The UN refugee agency is also monitoring the situation of those most vulnerable, identifying people at risk and with specific needs, including victims of sexual violence and arbitrary detention. UNHCR will also evaluate the need for shelter assistance in order to minimize the pressure on the host families and local community.

The total number of people displaced by violence and fighting in the eastern DRC is over 1.8 million.