Taleban insurgents in Afghanistan claim they have more suicide bombers waiting to strike a day after a bomber killed at least nine people in the capital, Kabul. The attack has stoked fears of fresh violence throughout the city.
Wednesday's suicide bombing was the first major attack in Kabul in more than a year and shattered a growing sense of security in the war-torn city.
Taleban insurgents claimed responsibility for the blast, which ripped through a crowd of Afghan soldiers waiting outside a military training center.
A Taleban spokesman also said scores of other would-be suicide bombers are waiting to launch attacks.
U.N. spokesman Adrian Edwards says the organization has tightened already strict security protocols for its staff in the Afghan capital.
"Right at the moment we are on restricted movement in Kabul and I think the situation is under continual review," said Mr. Edwards.
Thousands of aid workers and U.N. staff are based in Kabul, which has been considered more secure than other cities in Afghanistan.
Wednesday's bombing is the deadliest suicide bomb attack in the capital since U.S.-led forces ousted the Taleban in 2001.
Taleban insurgents have intensified their attacks in the past year, but most of the violence has occurred in Afghanistan's restive southern and eastern provinces.
The bombing has raised concerns that insurgents in Afghanistan could be adopting tactics used by Islamic militants in Iraq.
U.S. magazine Newsweek this month quoted a Taleban leader as saying he had recently been in Iraq where he had received training in insurgency techniques.