KABUL — A suicide car bomb exploded outside the main gate of the NATO-led military mission today, killing seven Afghans and wounding 91 in an attack that penetrated a heavily guarded neighborhood five days before the country's presidential election.

The bomber evaded several rings of Afghan police and detonated his explosives at the doorstep to the international military headquarters, an assault possibly aimed at sending the message that the Taliban can attack anywhere as Afghans gear up for their second-ever direct presidential election.

The Taliban claimed responsibility for the blast and said the bomb contained 1,100 pounds of explosives.

Afghanistan has braced for attacks ahead of the election. International workers were planning on working from home over the next week or had been encouraged to leave the country.

Meanwhile in the southern province of Helmand, Hawai'i-based U.S. Marines have been trying to secure the strategic town of Dahaneh to cut Taliban supply lines and enable the government to open a polling station there.

After two days of fighting, Marines helped Afghan officers raise the Afghan flag over the town yesterday after tribal elders assured the Americans there were no Taliban left there.

Soon after the flag-raising ceremony, the Marine base in the town came under small-arms, machine gun and rocket-propelled grenade fire, sending Marines running for cover. A patrol was sent out to find the gunmen and ended up locked in a lengthy gunfight that continued into the night.

President Hamid Karzai holds a strong lead in the Afghan presidential race but is still short of the majority he needs for a first-round victory, according to a U.S. government-funded poll released yesterday.

Karzai told a crowd of several thousand in the western city of Herat yesterday that if re-elected, his first priority would be to initiate talks with the Taliban and other insurgent groups.