A suicide bomber on Thursday targeted the motorcade of a senior police officer in the southern Pakistani port city of Karachi, killing four persons and injuring 14 others, officials said.
Witnesses said the attacker, who was riding a motorcycle, first opened fire and then blew himself up near an armoured vehicle in which Special Superintendent of Police Rao Anwar was travelling.
The attack occurred at a busy traffic roundabout in Malir area of Karachi. Four persons were killed instantly, witnesses and police officials said.
The injured were taken to nearby hospitals and officials said three of them were in a serious condition. SSP Rao Anwar said the attacker had hit the armoured vehicle with his motorcycle.
"People ran in panic after the blast. One of the policemen in my team was injured," he told the media.
No group has claimed responsibility for the attack but Anwar said he and some other officers had received threats from the Tehrik-e-Taliban Pakistan.
"There was an intelligence report about a month ago on the threat to us," he said. Additional Inspector General of Police Akhtar Gorchani too said some police officers had been receiving threats and Anwar was among them.
Police and paramilitary personnel cordoned off the area after the attack. Officials of the bomb disposal squad said about five kilograms of explosives were used in the attack.
They said they had found the mutilated head of the attacker, who was aged between 20 and 25 years.
Footage on television showed that the armoured vehicle was peppered by ball bearings that were packed into the attacker's suicide vest.