KABUL?Afghanistan authorities and international forces are securing the capital Kabul against Taliban attacks expected to coincide with the inauguration of President Hamid Karzai, scheduled for Thursday.

The city's airport, controlled by North Atlantic Treaty Organization (NATO)'s International Security Assistance Force (ISAF) will close for the day, an ISAF officer told AFP.

"There will be no air movements in or out, except for night Hajj flights" taking Muslim pilgrims to Mecca, he said, speaking on condition of anonymity.

International troops will be on standby to assist Afghan security forces in the event of an attack, he said.

Security companies are recommending clients order all international staff to remain indoors, at home, amid wide expectations of suicide bomb and rocket attacks.

The United Nations is also expected to order international staff to remain indoors, as major roads around Kabul will be closed to traffic.

Foreign staff at some UN agencies said they are in "lockdown"?not permitted off their premises?for three days around the ceremony.

"I'm betting on at least three or four rockets into the palace at 6:30 on Thursday morning," said one senior Western official, who also declined to be identified.

He said requests to the president's office for added security for non-government organizations in Kabul have been ignored and as a result "NGOs are feeling a lot more vulnerable".

"Karzai has done nothing to reassure international workers that he is stepping up security. We're on our own in this town now," he said.

Karzai is due to be sworn in as president for another five years at a ceremony?described by his office as "glorious"?at the heavily fortified presidential palace in the center of the capital.

Western and regional foreign ministers are expected to attend, along with hundreds of Afghan dignitaries and local and foreign correspondents.

Karzai's inauguration is controversial as it follows an August 20 election marred by massive ballot-stuffing?mostly in Karzai's favor?and the withdrawal of his main challenger Abdullah Abdullah from a run-off.

To many Afghans, Karzai's presidency lacks legitimacy, his government lacks authority and the way in which he took the presidency lacks credibility.

The Taliban considers him a puppet of the US and NATO, which together have more than 100,000 troops in Afghanistan, battling to defeat the insurgency.

Western diplomats and officials in Kabul, as well as security and military experts, said they expect Taliban attacks around the inauguration.

Rockets are occasionally fired over Kabul from outlying villages, in what diplomats say is a Taliban intimidation tactic, but rarely cause casualties.

In recent months, the militant organization has launched devastating suicide car bomb attacks that have killed up to 100 people in the capital alone.

The Taliban waged a vicious campaign around the August 20 election and threatened a repeat for the run-off, which had been scheduled for November 7.

True to their word, before the run-off was cancelled militants attacked a UN guesthouse in downtown Kabul, killing five UN election workers.

The attack traumatized the foreign population of Kabul, and saw the UN withdraw up to 600 staff, of a total of 1,300 in the country.

A UN official told AFP that only "a couple of hundred" foreign employees remain in Afghanistan, and "they will be in lockdown on Thursday".

Security experts and diplomats said they expect that attacks that had been planned to derail the November 7 run-off could be deferred to the inauguration.

"They've got everything in place, why waste it?" said one security company executive.