KABUL — A suicide bomber on foot penetrated one of the most closely defended parts of Kabul on Saturday, blowing himself up outside a carpet shop a few hundred yards from international embassies and the walls of the NATO headquarters and killing at least six Afghan civilians, including some children.
The bombing punctuated a tense holiday in commemoration of a mujahedeen commander, killed in 2001, for which security had already been increased in Kabul.
Clashes between his supporters and other ethnic groups and the police in a Kabul neighborhood left cars tipped over and on fire, police guard posts burning, and at least two dead, an indication that ethnic tensions remain combustible here.
The blast did not kill any foreigners or harm NATO installations.
But it showed the ability of insurgents to reach inside the central district only a few hundred yards from the US Embassy, the Afghan presidential palace, and NATO compounds.
The Taliban claimed responsibility, saying the target was a nearby CIA installation.
Asked whether the bombing had been directed at a CIA property, Jamie Graybeal, a spokesman for the International Security Assistance Force, the formal name of the NATO-led military coalition, said, ‘‘We do not feel it appropriate to talk about what the Taliban was trying to target.’’
The Interior Ministry said six people were killed in the attack, and four others were wounded. But at the scene of the bombing, the bodies of six children and two adults lay sprawled beneath trees on the side of the road opposite the Spanish Embassy and the residence of the Indian ambassador.
Witnesses said the number of deaths could be even higher. The police took away some victims soon after the attack, said Abdul Jamil, 38, a resident.
‘‘I saw about 12 bodies, all were civilians,’’ he said. ‘‘I saw a little girl whose legs were blown away in the back of the police truck.’’
The explosion rocked the center of the capital around 11:30 a.m. General Daoud Amin, the Kabul deputy police chief, said the attacker had approached on foot carrying a backpack. Street vendors, many young children who easily pass the many checkpoints, typically bring scarves, hats, and other merchandise in sacks to sell to foreigners near the NATO base and embassies.
Amin and other officials said the attacker was a boy, 12 to 15 years old. They pointed to severed legs on the street, which they said were those of the bomber.
The US Embassy and ISAF both issued statements condemning the use of a child to carry out the attack.
But the Taliban said the assailant was 28 and from Logar Province.
“Conducting such a successful attack on an important CIA center in Kabul City is something that a 12-year-old boy is not able to do,’’ said Zabiullah Mujahid, a Taliban spokesman.
The attack came a day after the United States designated a Taliban affiliate, the Haqqani network, as a terrorist group. The Haqqanis have carried out attacks in Kabul.
A NATO official in Kabul said the coalition did not know whether the Haqqanis were responsible.
‘‘I don’t think you can link the two,’’ the official said, referring also to the terrorist designation.
He asked not to be identified because the investigation was still underway. But a spokesman for the Afghan Interior Ministry, Siddiq Siddiqi, said in a Twitter message he thought the Haqqanis were behind the attack.