The African Union (AU) has strongly condemned the killing over the weekend of three Nigerian peacekeepers and two civilians by suspected Sudan Liberation Movement/Army (SLM/A) rebels in Darfur.
The peacekeepers were serving with the AU Mission in Sudan (AMIS) while the two civilians were drivers employed by an AMIS contractor.
The AU also expressed concern about the abduction on Sunday - by what is believed to be members of a splinter group of the rebel Justice and Equality Movement (JEM) - of up to 40 members of its ceasefire monitoring team and their rescuers in the region.
However, media reports on Monday indicated that the hostages had been released.
"The Chairperson of the [AU] Commission [Alpha Oumar Konare] expresses his utter indignation at the killings and at the turn of events in Darfur in the last few weeks," an AU statement said.
Two AMIS peacekeepers and two civilian contractors were killed in an ambush on Saturday in Nyala, the capital of South Darfur State. A third soldier died on Sunday from injuries suffered during the attack.
Konare said he "holds the SLA responsible for this wicked and atrocious act".
This is the first time the AU has suffered fatalities in the war-torn western Sudanese region since AU forces arrived there in 2004. From an initial force of 500, the contingent has grown to over 6,000.
The AU chairperson said he had decided to "dispatch a high level team to Darfur, to provide support to AMIS leadership and the entire personnel of AMIS and to hold discussions to prevent the recurrence of such incidents in future".
The attacks have raised concerns about the progress of peace talks between the government and the rebels. A sixth round of negotiations began in September in the Nigerian capital, Abuja, to try to end the war.
The conflict in Darfur pits Sudanese government troops and allied militias like the Janjawid against two main rebel groups - the SLM/A and the JEM - that claim to be fighting against the marginalisation of their region by the government.
According to the UN, at least 2.9 million people continue to be affected by the conflict, of whom 1.85 million are internally displaced or have fled to neighbouring Chad.