The attack in western Kabul on Saturday also wounded four civilians and a foreigner, said Gen. Ali Shah Paktiawal.

Zabiullah Mujahid, who claims to speak for the Taliban, claimed the group's responsibility for the blast.

Nato's International Security Assistance Force said it was looking into the report but had no immediate information.

"We were busy with our work making window frames. I heard a very strong sound, and when I turned around I saw a big fire in the street," said Mohammed Noor, 22, who owns a nearby carpentry shop. He said the blast fired bits of metal shorn from the attacker's car into his shop front.

Noor said he helped four seriously wounded people into cars to ferry them to hospital. He said at least seven people were killed and 10 wounded were wounded a higher casualty toll than police offered.

Friday's attack in Tirin Kot in Uruzgan province killed 10 people, including five children and a Dutch soldier. Four Afghan men also were killed, said Gen. Abdul Qasem Khan, the provincial police chief.

Purported Taliban spokesmen have warned civilians to stay away from military convoys, but suicide bombings commonly kill or wound far more civilians than the intended military targets.

Violence has spiked in Afghanistan in recent weeks. More than 2,300 people have died in insurgency-related violence this year, according to an Associated Press count based on figures from US, Nato, UN and Afghan officials.

Much of it has been focused on the southern province of Helmand, where a coalition and Afghan patrol was attacked by militants near Sangin district Thursday. The troops fired back and called in airstrikes.

"More than two dozen enemy fighters were estimated killed during the nine-hour battle and there are no reports of Afghan civilian injuries," a statement said.

In eastern Afghanistan, a coalition service member was killed in a clash in Paktika province Friday, the coalition said. The soldier's nationality was not released, but most troops in the east are American.