The dead included three civilians and one police officer. Kabul Police Chief Esmatullah Daulatzai said the suicide attacker blew up the car after police officers tried to stop him.
"A taxi was coming from Darul-Aman toward the city. Then police identified the taxi and tried to stop it and open the door of the taxi, the attacker set off explosives," Dauladzai said. "The attacker and his car exploded into pieces," he added.
At least four people were wounded in the blast. The attacker's target was not known.
It was the third suicide bombing in the Afghan capital this year.
Meanwhile, Afghanistan's President Hamid Karzai said today that he met with Taliban militants in attempts to bring peace to the country.
Karzai made his comments at a news conference in Kabul. He did not disclose details of the meetings or indicate if they included talks with senior militant leaders.
Karzai urged supporters of the fundamentalist Islamic militia to lay down their arms and join his government but ruled out any deals with foreign militants.
(compiled from agency reports)
