Nato troops joined a fight against a Taliban suicide squad that stormed a Kabul police headquarters today, unleashing a stand-off that lasted for more than five hours.

According to public health officials 18 people, most of them civilians, were wounded in the attack against the Kabul traffic police headquarters that began with a suicide car bombing.

Mohammad Ayoub Salangi, the Kabul police chief said two attackers, armed with assault rifles and suicide vests were shot dead as they tried to enter the five-storey building and “one or two” other gunmen were fighting back.

“Two attackers are killed by our police. One or two others are inside the building and fighting back. We have taken most of the building and we will clear the building very soon,” Salangi told AFP from the scene in west Kabul.

Sediq Sediqqi, an interior ministry spokesman, gave a similar account and the Kabul CID chief, Mohammad Zahir, told local television that four police officers were slightly wounded in the attack.

According to witnesses a large pall of smoke was rising from the police building and sporadic gunfire and explosions, likely hand grenades, could still be heard.An AFP photographer said Norwegian soldiers fired at the police building. 

Nato’s International Security Assistance Force (ISAF) confirmed its participation in the operation. “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.

He refused to give further details.

A local resident told AFP the attack started with a massive explosion that shattered the windows of nearby homes.

He said the initial explosion “very very big — it was massive”, and was followed by several other explosions and gunfire.“There are firefighter trucks, ambulances and police all over the place. The gunfire comes from that direction and the building’s top floors are on fire,” he said.

Taliban insurgents, who are waging an 11-year war against the Western-backed government of President Hamid Karzai, claimed credit for the attack, which it said began at 5 am (0030 GMT).