A bomb explosion on a main road in Kabul today killed three Afghan policemen at an improvised checkpoint.
The bomb destroyed a shipping container being used as a security post on a road leading to Kabul airport, the chief of Kabul's rapid reaction police force said.
The blast, which was caused by a remote controlled device, also damaged a UN vehicle, but no UN staff were wounded.
Police said the attack may have been the work of Taliban militants, but no arrests have been made.
Kabul has been the scene of several bomb attacks since US-led forces overthrew the Taliban government in late 2001 seeking to flush out Osama bin Laden and his al-Qaeda network.
The bombing follows an attack yesterday in which a US soldier was killed and seven wounded in the Kunar province, where 19 US troops were killed in clashes with insurgents last month.
The US military said six of its troops caught in yesterday's attack were in a stable condition.
A US soldier was also killed and another wounded in an insurgent attack in the southern province of Helmand yesterday.
Agencies