KABUL - A suicide bomber walked into the offices of the Kabul police chief on Sunday and detonated his explosives, killing a senior aide in an attack that highlighted poor security procedures in the Afghan capital.
Kabul police chief Zahir Zahir told AFP that the attacker had penetrated the force's heavily-guarded headquarters by wearing a police uniform.
"I'm fine, but one of my best officers, my chief of staff Yassin Khan, was killed and six were wounded," Zahir said, speaking just an hour after the explosion rocked central Kabul.
"It was a suicide bomber with police uniform on. As he was stopped trying to enter my room, he detonated his explosives.
"We are investigating how he entered the police headquarters."
The Taliban claimed responsibility for the attack.
"This morning at around 9:00 am, a martyrdom attack was carried out against the enemy which killed a lot of them," Zabiullah Mujahid, a Taliban spokesman, said on his Twitter account.
"The attack was carried out by Maulawi Yaya Badakhshani inside Kabul police HQ while foreign advisors and police were meeting."
There were no immediate reports of foreign casualties, and the Taliban often exaggerate death tolls after attacks.
Kabul is regularly hit by Taliban bombings, with the military, police and government officials among those targeted despite heightening security with multiple checkpoints, guard posts and armed convoys.
In the last major blast, four Afghan soldiers were killed and around a dozen people - including six civilians - wounded when a roadside bomb planted by the Taliban exploded on October 21.
That blast was a remote-controlled bomb targeting an Afghan army bus. Afghan soldiers and police have taken on the lead role in thwarting the Taliban, but national stability could be at risk as US-led NATO troops pull out.
This year alone more than 4,600 Afghan soldiers and police have been killed in fighting, according to recent US figures.
US-led NATO troops end their 13-year combat mission in Afghanistan next month, with about 12,500 soldiers due to stay on into next year on a training and support mission.
President Ashraf Ghani, who came to power in September, has said that Afghan forces are ready to impose security.
This summer the Taliban launched several offensives during a prolonged political deadlock in Kabul as Ghani and his rival Abdullah Abdullah both claimed to have won the fraud-mired presidential election.
The two men eventually signed a power-sharing agreement, with Abdullah appointed to the new position of "chief executive".
NATO troop numbers peaked at 130,000 in 2010, but now stand at less than 34,000.