By Simon Apiku

KHARTOUM, June 18 (Reuters) - Car-jackings, abductions and ambushes are hindering aid workers involved the world's biggest humanitarian relief effort in Sudan's violent Darfur region, a U.N. report obtained by Reuters on Monday said.

A record 68 aid vehicles were ambushed in the first five months of 2007 and 23 of those attacks involved abductions, the U.N. security report said.

"The trend is still going upwards," it added. "Altogether 77 humanitarian workers have been abducted in that way."

In April, five Senegalese African Union peacekeepers were killed during a car-jacking. The struggling mission has had dozens of vehicles stolen as it has become a target for warring factions in the rebellion in the remote west of Sudan.

Some 14,000 aid workers look after 2.5 million Darfuris forced to seek shelter in miserable camps, and international experts estimate 200,000 people have died in more than four years of rape, killing, looting and disease in the region.

The International Criminal Court has issued arrest warrants for a junior Sudanese cabinet minister and a militia leader accused of colluding in war crimes in Darfur.

The report said there was a high risk of being injured in the confrontations between car-jackers and security forces or in car chases or by being abandoned without communications gear, water or protection.

Those abducted are usually released unharmed but it is "a traumatic experience that leaves psychological scars", it said.

Last week, Sudan agreed to a combined U.N.-AU peacekeeping force of troops and police in Darfur. The United Nations hopes this will improve security in the region bordering Chad.

"There is growing evidence that many of the (stolen) vehicles are being transferred to Chad, where they are sold through intermediate criminal groups," the report said.

Darfur rebels, Chadian opposition forces and Arab militia groups also have reasons to steal vehicles, it added.

With roads becoming more dangerous, humanitarian workers rely for help on aircraft operated by the World Food Programme (WFP), which has enough funding to keep flying until October.

Mostly non-Arab rebels took up arms in Darfur in early 2003, accusing the central government of neglect.

AlertNet news is provided by