It has emerged that an aid worker and 10 civilians died two weeks ago after being taken hostage in south-east Democratic Republic of Congo.
Some 3m Congolese civilians have died in the five-year conflict
A UN spokesman disclosed that the group had been working on a water supply project supported by a British charity, Tearfund, when they were taken captive by Rwandan and Burundian rebels.
Congolese hydraulic engineer Maheshe Chishagala Evariste and local civilians had been trying to provide water to the town of Baraka since February this year.
Rebel groups are still fighting in many eastern parts of Congo, despite reaching peace deals with the government in Kinshasa.
A French-led peacekeeping force is deployed further north in Bunia in Ituri Province, which saw heavy fighting between rival militia groups earlier this year.
A Tearfund spokesperson told BBC News Online that the organisation had suspended their operations in the immediate area and had sent someone out from the UK to investigate the security situation and the circumstances of their deaths.
Tearfund employs some 20 staff in South Kivu working on water, sanitation and public health projects.
There are several thousand peacekeepers deployed in DR Congo and their mandate has recently been strengthened.
But they have been fiercely criticised for failing to protect the civilian population in the Ituri region.