A suicide bomber has blown himself up near Nato headquarters in Kabul, killing at least six people, according to Afghan authorities.
Kabul deputy police chief Daud Amin said the US Embassy, the Italian embassy and the presidential palace are also located near the site of the attack.
The ministry of interior said six people were killed and five others were wounded.
The attack came as Afghans marked the 11th anniversary of the death of Ahmad Shah Massoud, the charismatic Northern Alliance commander who was killed in an al Qaida suicide bombing two days before the September 11, 2001, attacks.
The alliance joined with the United States to help rout the Taliban after America invaded Afghanistan a month later in the wake of the attacks.
Taliban spokesman Zabiullah Mujahid said in a statement emailed to reporters that the bombing was carried out by a 28-year-old militant from Logar province, south of Kabul.
But Kabul deputy police chief Daud Amin said eyewitnesses reported seeing a teenage boy, who was aged about 13 or 14, walking in the area carrying a bag.
Interior ministry spokesman Sediq Sediqi blamed the attack on the Haqqani network, one of the most dangerous militant groups fighting US-led forces in Afghanistan. He did not say what he was basing that conclusion on, but the Haqqani group, which is linked to both the Taliban and al Qaida, has been responsible for several high-profile attacks in the Afghan capital in the past.
On Friday, the US designated the Pakistan-based Haqqani network a terrorist organisation, a move that bans Americans from doing business with members of the group and blocks any assets it holds in the United States.
The Obama administration went forward with the decision despite misgivings about how the largely symbolic act could further stall planned Afghan peace talks or put yet another chill on the United States' already fragile counter-terrorism alliance with Pakistan.