A car bomb rammed a convoy of foreign troops near the main airport in Afghanistan's capital on Sunday, killing at least three civilians in the latest attack in the city, police and a witness said.

The NATO force in Afghanistan said it could not confirm if any of its vehicles had been hit.

There was no immediate claim of responsibility, though Taliban insurgents have launched a wave of attacks around the country since the drawdown of most foreign troops last year to a small training force.

Police spokesman Ebadullah Karimi said a suicide bomber in a Toyota Corolla rammed a convoy of foreign troops on the road from Kabul's main airport to a NATO military installation nearby.

The bomber struck about 200 metres from the main airport entrance along the road leading to NATO's adjacent base.

Reuters TV footage showed the mangled remains of the car.

Rescuers carried wounded Afghan civilians from the scene, which police cordoned off.

Shopkeeper Fraidon Khan said he witnessed the car slam into a convoy of foreigners.

"I saw three dead bodies. One of them was a child and two were women," he said.

A spokesman for NATO's Resolute Support mission said there was no early confirmation that a coalition vehicle had been hit and referred queries to the Afghan Ministry of Interior.

"It just happened, so we're still tracking it," said public affairs officer Armando B. Perez.