At least four people were killed and 15 others injured in a suicide bomb attack in Pakistan's southern port city of Karachi on Thursday morning, reported local Urdu TV channel ARY.

People gather around a destroyed motorbike at the blast site in southern Pakistani port city of Karachi, on April 5, 2012. At least four people were killed and 15 others injured in a suicide bomb attack in Karachi on Thursday, reported local Urdu TV channel ARY. (Xinhua/Masroor)
Hospital sources said that at least two or three injured people were in critical condition.

The killed include two policemen.

Pakistan Taliban has claimed responsibilities for the attack.

The attack occurred at about 11:30 a.m. local time when a man riding on a motorcycle blew himself up near a police vehicle on a busy road in the Malir Halt area of Karachi.

The target of the attack was believed Rao Anwar, senior superintendent police of Malir Halt area in Karachi. Rao escaped the attack as he was sitting inside an armored police vehicle, but his vehicle and two escort police mobiles were damaged.

Rao was on his way to office when he was attacked. He said that he had received life threats from Taliban the previous days and that was why he chose to use an armored vehicle while on duty.

"They can't scare me. I am more determined to perform my duties after the attack," Rad told local media.

Local media quoted eyewitnesses as saying that four or five militants were involved in the attack and they first opened fire on the police convoy before one of them hit the police vehicle with his motorbike.

Police have arrested one suspect on the spot in the search operation following the blast.

Bomb disposal squad said that an estimated five to six kg of explosives were used in the suicide jacket.

Identity of the suicide bomber is yet to be determined, said police.

Earlier on Thursday, three policemen were shot dead by unknown gunmen while performing duty at a flourmill in the PIB Colony of Karach.

Following the two separate attacks on police in Karachi, there came reports that a remote-controlled bomb planted on roadside hit a police vehicle in Pakistan's southwestern city of Turbet on Thursday, killing three policemen and wounding two others.

VietNamNet/Xinhuanet