A suicide bomber dressed in an army uniform rammed his motorcycle into a fleet of buses carrying Afghan army officers in the capital Kabul on Wednesday, killing at least nine people and wounding 28, officials said.
The Taleban claimed responsibility for the attack at the Kabul Military Training Centre, set up by US-led forces to train a new national army, and warned that more could be expected.
It was the bloodiest of several suicide attacks in the Afghan capital since US-led forces overthrew the Taleban in late 2001 and came just 10 days after landmark parliamentary elections, which passed off relatively peacefully despite militant threats.
Defence Ministry spokesman Zahir Azimi said 10 people had been killed, including the bomber. He said most of the dead were army officers. Another ministry official said eight of the dead were soldiers and another a civilian.
"It was a suicide attack," Azimi said. The person was wearing an army uniform and was on a motorbike which he rammed into the convoy of the National Army officers."
Four minibuses that had been carrying soldiers were burned in the attack, witnesses said.
Mohammad Akbar, the police chief of the eastern city district where the blast took place, said the attacker struck the buses in the car park of the training centre.
Witness Mohammad Gul, 32, said he saw a motorcyclist ride into the car park. "Suddenly there was a huge explosion. It was deafening and I still can't hear properly," he said.
Major Andy Elmes, a spokesman for the Nato-led International Security Assistance Force peacekeepers, said ISAF had rushed teams to help treat and evacuate casualties.
"It was horrible," said another witness, Gul Mohammad. "There was a huge blast. The vehicles caught fire, I don't know how many, and the soldiers were rushing into the wreckage to pull people out. I was terrified - I just ran away."
Taleban spokesman Abdul Latif Hakimi named the bomber as Kabul resident Sardar Mohammad and warned that the guerrillas planned more such attacks.
"More mujahideen (holy warriors) suiciders are ready to follow his way and you will witness them doing it in the future," he said by satellite phone from an undisclosed location.
Elsewhere on Wednesday, three people were killed and five wounded in a mine blast in the eastern province of Kunar and on Tuesday, a Bangladeshi UN worker was critically hurt by a roadside bomb in adjacent Nangarhar province.
The Taleban also claimed responsibility for killing a parliamentary candidate in the northern province of Balkh on Tuesday, although guerrilla involvement could not be verified.