A suicide car bomber on Saturday killed 13 troops and civilian employees of the NATO-led force in Kabul, including Americans and a Canadian, in the deadliest single ground attack against the coalition in 10 years of war in Afghanistan.

Five International Security Assistance Force service members and eight ISAF civilian employees died following a suicide vehicle-born improvised explosive device attack in Kabul earlier today, the ISAF said in a statement reported by Reuters.

The Taliban has claimed responsibility for the attack.

The attack in the Darulaman area, southwest of Kabul, also killed three Afghan civilians and a policeman.

BBC correspondent Quentin Sommerville, who is in Kabul, commented: “The Taliban have been pushed back in the south of the country -- their traditional heartland -- where ISAF has made a lot of progress. But there are hot spots there and in the east of the country. There has been a shift in the Taliban's tactics -- they are adaptable, in the way they match their attacks to a changed international mission.”

Sommerville added that attacks on members of the ISAF are down, but assassinations have dramatically risen by 60 percent, as have roadside bombs. There has been some success in stopping attacks, but, as NATO commanders say, Militants have to be lucky only once -- we have to be lucky every day.”

The murderous attack will surely worsen relations between the U.S. and Pakistan, which has been accused of fostering relations with both the Taliban and the Haqqani terror network.

Based in Pakistan, the Haqqani network reportedly launched an attack on the U.S. embassy and ISAF headquarters in Kabul in September.

Separately, NATO also said that a man wearing an Afghan military uniform killed three Australian soldiers in the southern part of the country. The gunman himself was also killed.

While 130,000 foreign troops remain in Afghanistan, the U.S. plans a complete withdrawal by 2014.

The U.S. is planning to withdraw its troops from Afghanistan and hand over security to local forces by 2014.