The NATO force made no immediate comment after the attack, which came as foreign troops rapidly wind down combat operations at the end of a 13-year war against Taliban insurgents.
"At around 11:30 am, a convoy of foreign forces was targeted by a suicide bomber in police district 6, killing four civilians and wounding seven," interior ministry spokesman Sediq Sediqqi said on his Twitter account.
A spokesman for the Taliban said the insurgents claimed responsibility for the attack.
"Several vehicles were damaged."
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