A Taleban suicide car bomb exploded Saturday outside the main gate of NATO's headquarters here five days before Afghanistan's presidential election, killing seven and wounding 91. It was the biggest attack in the Afghan capital in six months. The bomber evaded several rings of Afghan police and detonated his explosives on the doorstep of the international military headquarters, an assault possibly aimed at sending the message that the Taleban can attack anywhere as Afghans gear up for their second-ever direct presidential election. “The target was the US embassy, but we could not reach it,” Taleban spokesman Zabihullah Mujahid told news agencies by telephone from an undisclosed location. Mujahid said the bomb contained 1,100 pounds (500 kg) of explosives. Mujahid at first said the bomber was on foot, then later called back and said it was a suicide car bomb attack. The NATO headquarters – where top commander US Gen. Stanley McChrystal is based – sits beside the US Embassy and shares the same street as the presidential palace. The street is one of the most tightly secured in all Kabul. The blast shattered windows in the area and shook buildings in the Wazir Akbar Khan district, home to most major foreign embassies and organizations in the capital. It also rattled confidence in an Aug. 20 presidential election which pits incumbent Hamid Karzai against 35 challengers. Two recent polls have Karzai with a comfortable lead over his nearest challenger, Abdullah Abdullah, but not enough to avoid a second round run-off. Militants have warned Afghans not to vote and have threatened to attack voting sites. Karzai condemned the attack but said it would not stop Afghans from voting. “The enemies of Afghanistan try to create fear among people in this election period but people still realize the importance of going to ballot boxes to cast their votes,” Karzai said in a statement. A spokesman for the International Security Assistance Force said there were some ISAF casualties in Saturday's blast, while an official with the Afghan Ministry of Transport, whose headquarters bore the brunt of the blast, said dozens of employees were hurt by flying glass. The explosion was the first major attack in Kabul since February, when eight Taleban militants struck three government buildings simultaneously in the heart of the city, an assault that killed 20 people and the eight assailants. International workers in the country were planning on working from home over the next week or had been encouraged to leave the country. US,NATO and Afghan troops were working to protect voting sites, particularly in regions where militants hold sway. Other security developments in Afghanistan: • Afghan troops, backed by foreign air power, killed about 29 Taleban insurgents in an operation in southern Uruzgan province overnight, a Defense Ministry spokesman said. • Thirteen insurgents were killed in an airstrike called in by Afghan and foreign soldiers on a Taleban meeting in the Spera district of eastern Khost province Friday, said a spokesman for the provincial governor. • Afghan security forces killed two insurgents in clashes in eastern Paktika province Friday, the Defense Ministry said.