A Taliban suicide bomber targeted a NATO convoy in downtown Kabul Sunday, triggering a powerful explosion in a rush-hour attack that comes just days after the resurgent armed group overran a key northern city.

A Taliban suicide bomber targeted a NATO convoy in downtown Kabul Sunday, triggering a powerful explosion in a rush-hour attack that comes just days after the resurgent armed group overran a key northern city.

No casualties were immediately reported from the bombing, which sent a thick plume of smoke rising into the sky, as the Taliban ramp up attacks on government and foreign targets.

Security officials cordoned off the area as ambulances with wailing sirens rushed to the scene, which was littered with the mangled wreckage of vehicles.

A NATO spokesman in Kabul confirmed that their convoy came under attack but said the international coalition was still gathering further information.

Taliban spokesman Zabihullah Mujahid told AFP they were behind the bombing.

"A convoy of foreign forces came under martyrdom attack by our mujahideen in Joy Shir area of Kabul city. Two of their vehicles were damaged and all aboard the vehicles were killed," he said.

NATO forces are themselves under fire after a US air strike recently pummeled a hospital in Kunduz run by Doctors Without Borders (MSF).

The medical charity shut down the trauma centre, branding the incident a war crime and demanding an international investigation into the incident, which sparked an avalanche of global condemnation.

President Barack Obama has apologised over the strike, with three different investigations -- led by NATO, US forces and Afghan officials -- currently under way.

The Pentagon announced Saturday it would make compensation payments to those killed and injured in the strike.