Islamabad:
A suicide bomber struck a vehicle carrying a senior paramilitary police chief in North-Western Pakistan on Wednesday, killing him and four others in an attack that ended a period of relative calm in Peshawar city which has been a favourite target of the Taliban.
Sifwat Ghayur, the head of the 25,000-strong Frontier Constabulary, is one of the most senior security officials ever to be killed by militants in the country.
The attack comes as Pakistan's impoverished northwest has been struggling to recover from more than a week of devastating floods that killed 1,500 people and left millions looking for aid from the government.
The explosion also injured seven other people.
Rescue workers frantically tried to extinguish fires that engulfed several cars in the minutes after the bomb attack near a major market in the centre of Peshawar, which was wracked by bombings late last year but has been relatively quiet in recent months.
Ghayur was killed along with his driver and three bodyguards said a senior police officer. The explosion also injured 11 other people, he said.
The attack was filmed by a surveillance camera, which showed the bomber walking up to Ghayur's vehicle at a set of traffic lights and detonating his explosives.
The explosion ripped through several cars stopped at the lights.
What is believed to be the head of the suicide bomber was found in the street.
The Frontier Constabulary is a paramilitary police force that is primarily drawn from the northwest and operates throughout the country in support of traditional police officers.
There has been no claim of responsibility for the attack, but the Pakistani Taliban have frequently targeted security forces.
The Frontier Constabulary has worked with the army to battle the militant group, which is based in the country's semi-autonomous tribal regions along the border with Afghanistan.
Peshawar is in the centre of the conflict. It is the main city in the northwest, abuts the tribal regions and is just an hour's drive from the Afghan border.
The city was hit by almost daily bombings last autumn in retaliation for an army offensive against the Pakistani Taliban's main sanctuary in the South Waziristan tribal area.