Gunmen in Sudan's Darfur seized 31 displaced people travelling under peacekeeper escort to a refugee conference, the African Union-UN mission to the region said on Monday.
The mass abduction highlights insecurity for 1.4 million Darfuris uprooted by the region's decade-old conflict, and whose future is under discussion at the two-day conference which began on Monday.
"A convoy of three commercial buses carrying 31 internally displaced persons (IDPs) and escorted by UNAMID peacekeepers was stopped by a large unidentified armed group in military uniforms and seven jeep-mounted guns," UNAMID spokeswoman Aicha Elbasri said.
"Despite UNAMID opposition, the armed group forced the IDPs to an unknown location," said Elbasri, condemning the action of the gunmen.
Critics have previously accused UNAMID of not being aggressive enough in fulfilling its core mandate of protecting civilians. The mission has defended its role and said it has helped improve security in Sudan's western region.
Peacekeepers were unharmed in the incident, which happened at about 6:20 pm (1520 GMT) on Sunday at a border crossing between Central and South Darfur states, Elbasri said.
A Nigerian battalion is in charge of the area for UNAMID.
Sources in the region told AFP the peacekeepers were outnumbered, and that the incident occurred near a Sudanese government checkpoint.
Elbasri said it is unclear whether the captives have already been released.
"Some of them are safe," Abdulbagi Ahmed Suliman, media director of Darfur's Voluntary Return and Resettlement Commission, told AFP from the main South Darfur city of Nyala.
But he said the status of the other displaced people who were captured remained uncertain.
They were on their way from Zalingei, the capital of Central Darfur, to Nyala where a government-run conference on Darfur's IDPs and refugees is taking place at a heavily-guarded hotel.
Suliman said more than 270 IDPs from across Darfur had safely reached the meeting, along with around 70 refugees, mostly from neighbouring Chad.
They were to set out their needs for returning to their villages to an audience of hundreds of civil society, UN, government and other delegates, he said from the conference venue.
But he added that they had already made their overriding concern clear: "Security, security, security."
The UN says 1.4 million people are still living in camps a decade after rebels from the Fur, Zaghawa and other indigenous ethnic groups began an insurrection seeking an end to what they said was the domination of Sudan's power and wealth by Arab elites.
In response, government-backed Arab Janjaweed militia shocked the world with atrocities against ethnic minority civilians. Villages were burned to the ground.
Although the worst of the violence has long past, rebel-government clashes continue and inter-ethnic fighting, banditry and battles between Arab and government forces further complicate the situation.
"Even the IDP camp itself is not really that secure," with government-linked guards blamed for instability, a humanitarian source said.
A UN report cited several factors undermining the return of IDPs in large numbers.
"These include the absence of a comprehensive political settlement" bringing in all rebel groups, as well as "unresolved issues of land tenure and occupancy, tribal clashes, high levels of criminality, food insecurity, deteriorating environmental conditions and very limited rural infrastructure."
Mohammed, 64, told AFP he left his East Darfur village with his youngest children five years ago for neighbouring South Kordofan state.
Like many others, he had become fed up with the "armed groups" shooting and looting around the village, hindering their ability to grow crops.
"If security improves... it's better for me to go back to my village," said Mohammed, which is not his real name. "It's my home."