Kabul, 2 Nov(AKI ) - United Nations secretary-general Ban Ki-moon has made a surprise visit to Afghanistan to meet president Hamid Karzai amid continuing confusion about the country's presidential election. Ban was also expected to meet former foreign minister Abdullah Abdullah who withdrew from the 7 November run-off election on Sunday.

The withdrawal of Abdullah has cast further doubt about the future legitimacy of the government, which will certainly be led by Karzai.

Ban also intended to show solidarity with UN staff following a Taliban attack which killed five staff members last week.

The head of the Independent Election Commission said he was concerned about security risks associated with a new election, a day after the commission said it would press ahead with the vote.

There is still confusion over whether the second round will proceed on Saturday.

Ban had welcomed the run-off when it was announced in October.

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

After Abdullah announced his withdrawal, the secretary-general' special envoy, Kai Eide, said "the next step must be to bring this electoral process to a conclusion in a legal and timely manner".

Abdullah's decision was clearly "taken after a long period of discussion and reflection," Eide said in a statement.

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.

US Secretary of State Hillary Clinton said she respected Abdullah's choice and urged him to still work for peace.