Fifteen killed in attack blamed on al-Qa'ida

At least 15 passengers on a minibus were killed in Afghanistan yesterday in an attack by Islamist militants trying to undermine the US-backed government of President Hamid Karzai.

Police said they were "100 per cent sure" that a bomb, which destroyed the vehicle on a bridge half a mile from an Afghan army post, was the work of al-Qa'ida and Taliban elements. It was the most serious attack since 26 people were killed by a car bomb in Kabul last September – the same day as an attempt to kill Mr Karzai was thwarted.

Rebel attacks on the US military and its Afghan allies have been growing steadily in recent months, and have been becoming increasingly bold. Yesterday's attack came a day after an American Black Hawk helicopter crashed on a night-time training mission near Bagram air base, killing four.

Earlier in the week US forces fought the fiercest battle for nearly a year. B-1 bombers and F-16s were used to attack militants in mountains in the south-east of the country. US officials said they killed 18.

In yesterday's attack a land-mine linked to a mortar, blew a metre-deep crater in the road near Kandahar. Police, who believe the targets were Afghan soldiers from the nearby base, said the only survivors were the driver and a boy of 12, whose uncle and father were killed. Police believe the attackers may have included militants loyal to the former Afghan prime minister Gulbuddin Hekmatyar, who the US believes has been forging links with al-Qa'ida and Taliban in the name of jihad against the US.

Witnesses described horrific scenes. Toori Ali, a nomad, said: "I was with my two children and we heard this loud noise. I ran away from it but then we heard people screaming, we went to help. It is the worst thing I have ever seen. There were body parts and only a small child and the driver lived."

Several Afghan soldiers were killed in a similar blast about two months ago in Kandahar when a bomb went off beneath their vehicle. The area used to be the heartland of the Taliban before they were ousted from power by the US-led assault on Afghanistan.

There was disagreement over whether al-Qa'ida was involved in yesterday's attack or whether it was primarily the work of the Taliban and Mr Hekmatyar's men. The deputy police chief, Ustad Nazir Jan, said he was "100 per cent sure that it was the Taliban and al-Qa'ida ... we will get the proof". He also said he suspected Mr Hekmatyar's involvement.

But Kandahar's provincial spokesman, Khalid Pashtun, said he thought it was more likely to be Taliban and Mr Hekmatyar because "al-Qai'da are now gone ... finished".

The attack was condemned by President Karzai's spokesman, Sayed Fazl Akbar, who said it only strengthened the need for foreign troops.