Story highlights The police chief's spokesman says it was a suicide attack

The convoy of contractors and civilians was the target, he says

The Taliban denies responsibility

Kabul, Afghanistan (CNN) At least 12 people were killed and 66 others wounded in a suicide attack in Afghanistan's capital Saturday, the spokesman for Kabul's police chief said.

Three American contractors with the NATO-led Resolute Support mission were killed, two of them as a result of their wounds, in what the mission described as an attack on their convoy from a vehicle-borne improvised explosive device.

The police chief spokesman, Ebadullah Karimi, said the bomber blew up his explosives-laden Toyota Corolla in the Macrorayan area of Kabul on Saturday afternoon. The convoy of contractors and Afghan civilians was the target, he said.

The explosion jolted central Kabul and broke the windows of dozens of nearby apartments, Karimi said.

It happened during the afternoon rush hour in front of a private health clinic where dozens of people gather daily to see doctors.

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