A mass grave has been uncovered pushing the official death toll to over 300 from recent clashes between rival militias in the north-east Democratic Republic of the Congo.
Militias have said French troops are not welcome
United Nations officials say some 30 bodies were found in a grave on the outskirts in the regional capital, Bunia.
A fragile ceasefire is now in place, allowing aid workers to complete the task of recovering the bodies of the dead from streets and buildings previously too dangerous to access.
But the brutal clashes have led to calls for a multinational force to be deployed in the region.
Speaking from Bunia, the BBC's Ishbel Matheson says it is unclear whether the remains were those of civilians or of fighters from the rival Hema and Lendu militias.
But most of the bodies which have already been recovered are civilians shot at point blank range or hacked to pieces by machetes.
Dogs of war
There have been allegations of cannibalism during the conflict but a spokesman for the UN mission in DR Congo (Monuc) said these were difficult to confirm.
"Many of the bodies have had parts ripped out but it is difficult to say whether this is cannibal-style atrocities or not, as there are a lot of dogs who have been eating the bodies," said Hamadoun Toure.
Local people say they want the militias disarmed and the roads opened up so they can flee the town.
On Wednesday, human rights groups Amnesty International and Human Rights Watch urged international intervention, saying the 700-strong UN presence was insufficient and thousands of civilians were at risk.
French military observers have now left Bunia, where they had gone to investigate the possible deployment of a multinational force; they will also meet Monuc officials.
British officials are considering contributing to the force, alongside the French offer of 1,000 troops.
The health clinic by the main UN compound is crammed with people suffering from the most appalling injuries.
One woman who refused to give money to militiamen was slashed repeatedly with machetes, and saw her children killed in front of her, our correspondent said.
The bodies of two UN military observers who were killed in DR Congo last week have been flown to the capital, Kinshasa.
A memorial service will be held in their honour, before they are flown to their countries of origin - Jordan and Malawi.
The clashes erupted soon after the 9,000 strong Ugandan forces withdrew from Bunia about two weeks ago, as part of a wider peace deal.
Some 20,000 Congolese civilians have fled to Uganda since then, according to the UN refugee agency.
Bunia is said to be traumatised by violence
"We would all have been massacred on the way if it weren't for the large numbers of [withdrawing] Ugandan soldiers," one refugee told the BBC's Will Ross in western Uganda.
Hemas, traditionally cattle-raisers, and Lendus, predominantly farmers, have been in conflict for centuries for land and other resources in the area.
The rivalry has become more bloody because Ituri district around Bunia is rich with gold.
Neighbouring nations involved in the five-year DR Congo conflict - Uganda and Rwanda - armed both sides as proxy militias.
An estimated 50,000 people have died and some half a million people displaced from Ituri since 1999.