Two US soldiers were among 15 people yesterday killed in a car bomb attack in Kabul.
The suicide attack on a convoy also killed four foreign contractors and nine Afghan civilians.
A spokesman for the US Defence Secretary, confirmed that two US soldiers in the Nato military coalition were killed in the attack.
Islamic militant group, Hizb-e-Islami, claimed responsibility for the early morning attack, saying it had formed a new unit to attack foreign forces.
At least two children also died in the powerful explosion in eastern Kabul. The attacker rammed a car packed with explosives into the convoy as it passed the home of an Afghan politician.
Officials said more than 30 people were wounded.
A Kabul provincial police spokesman said: “The explosion was very big. It set the nearby buildings on fire.”
Kabul deputy police chief Daud Amin said it was difficult to immediately estimate how many were dead because the blast shredded many of the victims.
“We saw two dead bodies of children on the ground, but the rest of the bodies were scattered in pieces.”
A spokesman for the militant group said one of their operatives carried out the attack on what he described as two vehicles of American advisers.
He claimed that most of the American advisers were killed and their vehicles destroyed.
Hizb-e-Islami is headed by 65-year-old former warlord Gubuddin Hekmatyar, a former Afghan prime minister and one-time US ally who is now listed as a terrorist by Washington. The militia has thousands of fighters and followers across the country’s north and east.
The attack was the second in eight months claimed by Hizb-e-Islami.
In September, the militant group claimed a suicide car bombing that killed least 12 people. Hizb-e-Islami said the attack was revenge for the film Innocence Of Muslims, which was made by an Egyptian-born US citizen and infuriated Muslims for its negative depiction of the Prophet Mohammed.
Afghan President Hamid Karzai condemned the “cowardly” attack. “Terrorists and enemies of Afghanistan’s peace brutally targeted a residential area,” he said in a statement.
A local resident said: “I heard a terrible explosion and our whole building shook.”
The blast was the first major attack in Kabul since March, when a suicide bomber blew himself up near the defence ministry, killing nine people.
The latest attack comes during what has been a bloody month for Isaf in Afghanistan, with at least 15 foreign military personnel killed in separate incidents since the beginning of May.
The Taliban announced a “spring offensive” in April, saying it would target foreign military bases and diplomatic areas.