Unless rebel attacks against United Nations and other relief operations in a northern sector of Sudan’s strife-torn Darfur region stop immediately, the world organization will be forced to suspend all assistance to 450,000 vulnerable people living in the area until safety can bee assured, a top UN official warned today. Secretary-General Kofi Annan’s Special Representative for Sudan, Jan Pronk, called on the rebel Sudan Liberation Army (SLA) stop attacks on humanitarian workers in Darfur, where some 180,000 people have been killed and 2 million more uprooted in three years of fighting between the Government, pro-government militias and rebels. The UN will hold responsible the armed groups, including those related to the SLA, and their leaders for the failure to assist the extremely vulnerable populations under their control, the UN Mission in Sudan (UNMIS) said in a statement. Over the past few weeks, aid workers operating for UN agencies and non-governmental organisations (NGOs) have come under continuous attacks and harassment by armed groups in the Shangil Tobayi, Tawilla and Kutum areas of North Darfur, with several reports indicating that many of the attacks were waged by SLA factions. “Armed robbery and hijacking have endangered humanitarian workers assisting over 450,000 vulnerable people living in the area,” the statement added. “Moreover, credible information points to the use of hijacked vehicles for military purposes by these armed groups. This is unacceptable and contrary to international humanitarian law.” It noted that Mr. Pronk had appealed to the rebels to “take all necessary steps” to assure the safety of staff and property in the areas under their control. “Unless these attacks and harassment stop immediately, the UN and its partners will be obliged to suspend all relief assistance to this particular area till effective safety for humanitarian personnel and assets is guaranteed,” the statement said.