NATO troops joined a fight against a Taliban suicide squad that stormed a Kabul police headquarters at dawn today, killing three police officers and unleashing a stand-off that lasted for more than eight hours.

The Taliban claimed the attack, which turned into the longest stand-off between the insurgents and security forces in Kabul since a major co-ordinated raid on the capital lasted 18 hours in April last year.

Three of the five attackers were killed in the early part of the assault while two others wearing suicide vests holed up in the five-storey building in west Kabul and fired on security forces, a police officer told AFP.

They were later also killed.

"It's over. The last two terrorists are dead and they were not even given the chance to detonate their suicide vests," Kabul police chief General Mohammad Ayoub Salangi told AFP.

The reason it took so long to overpower the last two men was "because our boys acted very carefully," he said. "There were lots of important documents so we acted very carefully to not cause any damage to those documents."

Four traffic police, two members of the special forces and half a dozen civilians were wounded, deputy interior minister General Abdul Rahman said.

An AFP photographer said Norwegian soldiers were seen firing at the police building.

NATO's International Security Assistance Force (ISAF) confirmed its participation in the operation but insisted it was small.

"We do have a very small number of people assisting the Afghan security forces officials in the scene. It's primarily an advising role and absolutely the Afghan officials are in the lead," an ISAF spokesman told AFP.

NATO says the Taliban insurgency has been weakened and characterised the attack as a ploy to attract media attention, but the time it took to mop up the insurgents will be seen as an embarrassment.