The suicide car bomb was detonated near the gate of NATO's International Security Assistance Force (ISAF) office in the Wazir Akbar Khan district, where most of the major foreign embassies and organizations are located in Afghanistan's capital.

"Unfortunately, there are casualties," said Canadian Brigadier General Eric Tremblay, an ISAF spokesman. "There are Afghan civilians and there are ISAF military."

Taliban spokesman Zabihullah Mujahid confirmed that the Taliban was behind the bombing.

"It was carried out by one of our hero mujahid, Ahmad, and the target was the US embassy and NATO headquarters," Mujahid said in a telephone interview with the German news agency DPA.

The blast blew out windows and rattled building in the neighborhood and a large cloud of smoke rose from the site of the attack over Kabul. It also rattled the confidence of a nation preparing for only its second ever direct presidential election.

Security in Kabul and across the country has been tightened in advance of the August 20 polls, with 30,000 extra American troops in place. Security forces have increased their patrols and set up new checkpoints in Kabul.

Worries for election day

But many observers and Afghan civilians fear that the country is still not secure enough for an election.

Despite the relative calm over the last several months, the Taliban has conducted over 20 attacks against politicians taking part in the elections. Incumbent President Hamid Karzai's running mate Mohammad Qasim Fahin was attacked by militants in northern Afghanistan and one cameraman was wounded. Two workers of Karzai's main challenger, former foreign minister Abdullah Abdullah, were killed by gunmen.

"The government says it will install the polling stations in secure areas like the center of the district, but how can we go there from our village?" asked Rahim Jan Kako from the Zherai district in southern Afghanistan. "I voted last time despite threats, but what the election brought us was killing and destruction."

Independent Election Commission officials said this week that elections would not be able to be held in 10 districts unless those areas were secured. A mass abstention from the vote is currently being predicted by analysts. Such a low turnout could lead the new government to lack legitimacy in the eyes of the Afghan people.

hf/dpa/Reuters
Editor: Nick Amies