The NATO-led International Security Assistance Force (ISAF) experienced a bloody day in Afghanistan as the military alliance lost 16 service members on Saturday.

A suicide bomber detonated his explosive-laden car next to a military convoy in western Kabul at around noon, killing 13 foreign troops and four Afghans, including three civilians and a policeman, according to ISAF and Afghan official statements.

An ISAF spokesman did not identify the nationalities of the dead service members, but all the victims were reportedly Americans.

Taliban militants fighting Afghan and NATO-led troops have claimed responsibility for the deadly suicide attack.

Qari Yusuf Ahmadi, a purported spokesman for Taliban, told media from unknown location that a militant named Abdul Rahman carried out the suicide bombing.

Afghan President Hamid Karzai strongly condemned the attack as a coward terrorist attack in a statement released by his office.

In an earlier attack in southern Afghan province of Uruzgan, a man in Afghan military uniform shot dead three Australian soldiers and a local interpreter during morning training of Afghan soldiers, an Afghan army officer in the southern region General Abdul Hamid Wardak said.