16 killed in suicide strike on Nato convoy in Kabul

Berlusconi threatens to withdraw troops after six Italians perish in attack

Italy's Prime Minister, Silvio Berlusconi, raised the possibility of an early military withdrawal from Afghanistan last night after six Italian soldiers were killed by a suicide bomber in Kabul. At least 10 civilians were also killed when the bomber crashed a car packed with explosives into a Nato military convoy in the Afghan capital. A government spokesman said 55 others were injured in the deadliest attack in Kabul for more than a year.

"We are all convinced it is best for everyone to leave Afghanistan soon," Mr Berlusconi said in Rome. But he stressed that Italy would not take any unilateral decision to pull out its troops, who operate as part of the international Nato-led mission.

Witnesses said the bomber drove his red Toyota 4x4 alongside the Italian convoy as it crawled through slow-moving traffic on a busy road linking Kabul's airport with the diplomatic quarter. The blast destroyed vehicles, levelled shops and blew out windows more than half a mile away.

Charred body parts were scattered amid the wreckage of the Italian Humvees, which had been blown into oncoming traffic. A Taliban spokesman said the bomber was a resident of Kabul called Ehdayatullah. The bombing was the fourth in Kabul in five weeks. Also in the capital, President Hamid Karzai defended last month's presidential election against increasingly vociferous allegations of vote rigging.

"I believe firmly, firmly in the integrity of the election and the integrity of the Afghan people, and the integrity of the government in that process," he said at his heavily fortified palace. He conceded that some government officials had shown bias towards him but claimed the scale of the fraud was minimal. "It wasn't that big," he said. "If there was fraud, it was small; it happens all over the world."

Results showed he had a majority of the vote. But the publication of complete preliminary results had been overshadowed by an announcement from European Union election observers that 1.5 million ballots, a quarter of the vote, were suspect. With many of these going to Mr Karzai, the expectation is that a robust investigation will depress his lead enough to force a second round of voting.

The UN-backed watchdog investigating complaints has already thrown out 200,000 ballots and ordered a recount of 10 per cent of polling stations nationwide. The international community has been pressing the Independent Election Commission and the Electoral Complaints Commission to ensure everything is ready for more voting before snow starts cutting off remote communities at the end of October.