KABUL: Afghan authorities are investigating how a man wearing an explosives-packed vest was able to infiltrate the heavily guarded police headquarters in central Kabul on Sunday and attempt to assassinate the city’s chief of police.

The suicide bomber’s ability to pass through heavy security and make his way to within meters of Gen. Mohammad Zahir Zahir’s office has revived concerns that insurgents have penetrated Afghanistan’s security and intelligence forces.

The incident was a serious breach of security in the fortified center of the capital and has highlighted the vulnerability of Kabul to a determined and still-virulent Taleban insurgency as a dwindling number of US and NATO troops shift from a combat role to training and support by the end of this year.

Sediq Sediqqi, spokesman for the Interior Ministry, said the incident had raised questions about someone “wearing a suicide vest had breached security.”

“The man was wearing a civilian suit and had a file in his hand and the suicide vest under his clothes,” said Sediqqi.

“He was asking police directions to the chief of police’s office, saying he had papers to deliver to him. This is the procedure for anyone who wants to meet with the chief of police, so the police sent him in the right direction.”

Earlier, Zahir said that the man was wearing a military uniform. Sediqqi said that footage from closed-circuit television clearly showed the attacker’s route through the compound.

Zahir was not in his office on the third floor of the building at the time of the attack, around 9 a.m, Sediqqi said, “but he was definitely the target.”