KABUL - Afghanistan laid out plans for the November 7 run-off presidential vote on Thursday in an announcement criticized as insufficient to prevent fraud, a day after a Taliban attack on U.N. staff reinforced concerns about security.

Worries about security and a possible repeat of election fraud have mounted ahead of the run-off in Afghanistan's disputed vote which the resurgent Taliban have vowed to disrupt.

In the deadliest attack on the United Nations in decades, militants killed at least five U.N. foreign staff on Wednesday in an assault on a guest-house in central Kabul.

Preventing a repeat of fraud that compromised the first round vote is another big challenge after a U.N.-led inquiry tossed out a large chunk of President Hamid Karzai's votes in the August election.

The deputy head of Afghanistan's Independent Election Commission said the election would go as planned, with more polling centers open this time due to improved security.

We are fully prepared to hold the second round of the election as scheduled, Zekria Barakzai told reporters. He said 6,322 polling centers would open this time compared with 6,305 on August 20.

One Western diplomat said the announcement ran contrary to earlier suggestions to reduce the likelihood of fraud.

The numbers of polling locations that the IEC has announced are extremely disturbing, said the official. It's a similar number to the first round and in the same locations, and they appear not to have made any effort to crack down on attempted fraud for the run-off.

The United Nations had earlier said polling stations in areas where turnout was low in the first round due to bad security and where fraud had taken place should not open. Voters would be instead encouraged to cast ballots in safer locations.

TROOP DEPLOYMENT

Concerns about the election have cast a shadow over U.S. President Barack Obama's plans to deploy more troops to Afghanistan to fight the increasingly fierce insurgency.

Karzai agreed to the poll under severe global pressure after a U.N. fraud inquiry invalidated enough of his votes to cut his tally below 50 percent and trigger a run-off. His closest rival is ex-foreign minister, Abdullah Abdullah.

In apparently coordinated attacks on Wednesday, the Taliban also fired rockets on a foreign-owned luxury hotel near the presidential palace in Kabul.

At least five foreign U.N. staff, three Afghan police and one civilian died in the attack. Three Taliban suicide bombers were killed when they detonated their bombs inside the guest-house.

The Taliban said they had targeted the guest-house because of the United Nations's role in helping organize the run-off vote.

The United Nations, which has operated in Afghanistan for more than half a century, said the attack would not deter it from its work, adding however that it may review security measures.
It said it has received assurances from Interior Minister Hanif Atmar that security measures would be stepped up at U.N. facilities and for U.N. staff in Afghanistan.

Aid groups working in Kabul said they would take extra precautions during the election period. We think it is very important that humanitarian workers are protected, said Save the Children director of international operations, Greg Ramm.

This month has already been the deadliest for U.S. forces since the start of the war eight years ago.

The eight U.S. soldiers killed on Tuesday pushed the October death toll to 53, topping the previous high of 51 deaths in August, Pentagon officials said.

(Additional reporting by Golnar Motevali; Writing by Maria Golovnina; Editing by Bill Tarrant)