A 14-year-old suicide bomber detonated explosives near the heavily barricaded Nato headquarters in Kabul yesterday, killing six civilians including children, Nato and local officials said.

The bomber wore a vest packed with explosives and rode right up to the Nato gates on a bicycle, underscoring the insurgents’ ability to strike deep inside the Afghan capital, ahead of the withdrawal of most foreign combat forces by the end of 2014.

Pieces of flesh and splattered blood lay on the street near the base, where the small bodies of children were lifted into ambulances. Scores of young children peddle trinkets and chewing gum around the foreign bases, hoping to earn a bit of cash.

Wailing women in head-to-toe burqas who said they were the dead children’s mothers rushed shortly after the attack to the site, where small flip flops lay strewn in the mud.

Kabul Police, in a statement to media, said the bomber was 14 years old, without giving details.

The Taliban took responsibility for the attack, but denied they had deployed a teenage bomber, saying instead he was a 28-year-old who targeted the Kabul offices of the US Central Intelligence Agency.

Nato’s International Security Assistance Force condemned the use of children. “Forcing underage youth to do their dirty work again proves the insurgency’s despicable tactics,” said spokesman Brigadier General Gunter Katz.

The US embassy in Kabul said in a statement that using “the most impressionable and vulnerable”, such as a teenager, to carry out such attacks revealed the true nature of the insurgents.

Ministry of Interior spokesman Sediq Sediqqi said six civilians were killed in the attack, which took place just before noon, and five more wounded, including children.

Security was beefed up across the capital yesterday as celebrations were underway to commemorate the 11th anniversary of the death of Ahmad Shah Massoud, the hero of the 1980s war against Soviet forces, and later a fierce opponent to the Taliban.

Massoud was killed on September 9 by al-Qaeda militants posing as reporters.

Yesterday bombing was the latest example of how militants are able to strike the most secure parts of the Afghan capital even after more than a decade of fighting Western forces with far superior firepower.