The 7 November run-off was announced late last month after the UN-backed Electoral Complaints Commission (ECC) found evidence of fraud in the first round of voting on 20 August.

On the heels of Mr. Abdullah's announcement today, “the next step must be to bring this electoral process to a conclusion in a legal and timely manner,” Kai Eide, the Secretary-General's Special Envoy, said in a statement.

Mr. Abdullah's decision was clearly “taken after a long period of discussion and reflection,” and the UN official voiced hope that the former presidential candidate's reform proposals will be part of Afghanistan's future political agenda.

Last week, five UN staff members were killed and nine others injured in an attack, for which the Taliban has claimed responsibility, on a guest house in the capital, Kabul.

Jossie Esto of the Philippines, who worked for the UN Development Programme (UNDP) election team Louis Maxwell, a close protection officer from the United States Lawrence Mefful, a UN security officer from Ghana and Lydia Wonwene, a UNDP elections officer from Liberia, were killed in Wednesday's attack.

The identity of a fifth UN staff member killed when militants attacked the guest house, where 34 UN staffers were staying, still needs to be confirmed.

“These women and men went to Afghanistan with many talents. But they shared a common goal, that is, to help the Afghan people,” Secretary-General Ban Ki-moon told UN staff members on Friday.

“They went despite the risks. They went to support another election and the opportunity for the Afghan people to shape their destiny,” he said.

Both the Secretary-General and Mr. Eide pledged in the aftermath of the attack that the UN will continue its work in the country.

Mr. Ban said that the UN is urgently reviewing the security environment throughout Afghanistan, and is exploring the feasibility of bringing in additional security units to guard UN facilities and guest houses.

The UN will also be consolidating its staff now scattered among many different locations in Kabul and may suggest that personnel not directly engaged in critical duties be re-located over the coming weeks. In addition, Mr. Ban is dispatching a senior UN official to the Afghan capital to express sympathy and solidarity with the staff.

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UN mourns staff members killed in Kabul attack