
A U.S. soldier arrives to the scene where a suicide car bomber attacked a NATO convoy in Kabul, Afghanistan, Thursday, May 16, 2013. (Anja Niedringhaus)

KABUL — Two NATO service members, four NATO civilian contractors and six Afghan civilians, including schoolchildren, were killed when a suicide car bomber rammed a two-vehicle NATO convoy in the Afghan capital during Thursday morning's rush hour, NATO and Afghan government officials said.

NATO did not immediately release details on the nationalities of the force's six casualties, in line with its usual policy. But Afghan police officials at the scene said they had removed the bodies of four Americans from one armored vehicle, which was charred and mangled by the powerful explosion.

Police and health officials said six Afghan civilians were also killed and 35 wounded in the 8 a.m. attack, including children walking to school in a crowded eastern district of the capital known as Shah Shahid. The bomber died in his car.

Taliban insurgents did not claim responsibility for the bombing. There were reports that another insurgent group, Hezb-i-Islami, said it had carried out the attack.

A spokesman for Hezb-i-Islami, Haroon Zarghoon, told two foreign media outlets in Kabul that members of the group targeted the convoy as part of a new "martyrdom unit" aimed at foreign forces here. Hezb-i-Islami, headed by former Afghan guerrilla leader Gulbuddin Hekmatyar, is a smaller rival of the Taliban movement and has carried out only a few such attacks in the past.

Officials said the two armored vehicles were negotiating a bump in the road when a Toyota Corolla sedan rammed into one of them and exploded. The powerful blast, which could be heard several miles away, left a large crater in the road and numerous nearby houses and shops damaged.

"I heard firing first. When I looked from the window, I heard a big explosion and saw smoke and flame rising from the cars on the road," said Yar Mohammad, a policeman guarding a private bank in a two-story building overlooking the attack site.

"It was very powerful explosion and totally destroyed one of the vehicles used by foreign forces and several other cars," said Mohammad. He said he suffered minor wounds from window glass shattered by the blast.

One of the vehicles was destroyed. After the attack, it lay beside the road with pieces of armored plates strewn in various directions. The second vehicle was damaged and towed away by NATO forces after the blast, according to witnesses.

NATO and Afghan forces sealed off roads leading to the site for several hours. Anxious parents rushed to the area, looking for children who had been walking to a nearby school. They were barred from entering the attack site.

The attack was the first major bombing in Kabul since March, when a suicide bomber blew himself up near the Defense Ministry, killing a group of Afghans. But it came during a bloody month for foreign forces. At least 15 foreign military personnel have been killed in various incidents since the beginning of May.