A massive suicide car bomb ripped into Nato vehicles killing six Italian soldiers and 10 Afghan civilians yesterday in one of the deadliest attacks on Western troops in Kabul, officials said.

The bomber struck just after midday about 1.5 kilometres from the US embassy on the busy airport road, destroying at least one vehicle of the Nato-led International Security Assistance Force (ISAF).

Six Italian soldiers were killed and another three wounded, the Italian Defence Ministry announced, as the Taliban claimed one of the worst single attacks on the more than 100,000 Nato and US-led troops serving in Afghanistan.

A second armoured vehicle also with an Italian flag and marked with the ISAF logo was badly damaged, the blast scattering metal across the blood-stained road, where civilians staggered through the wreckage hunting for relatives.

"I thought that day had become night. When I came back, for minutes I couldn't see anything. Then I saw one man lying on the tarmac without a head," said shopkeeper Fawad.

Italian Defence Minister Ignazio La Russa told the Senate in Rome that 10 Italian paratroopers were travelling in two armoured vehicles when the suicide bomber struck, apparently in a white Toyota vehicle.

"Sadly I must confirm the loss of six human lives from the parachute regiment," he said. Italy is the sixth biggest contributor of Western forces fighting in Afghanistan with about 3,250 troops on the ground.

Afghanistan's Interior Ministry said 10 Afghan civilians were killed and 55 wounded in the attack.

Foreign military deaths in Afghanistan are at record levels - at least 365 in 2009 - and the mounting number of Western troops coming home in body bags has sent support for the war plummeting in Europe and the US.