Pakistani Taliban claimed responsibility for the suicide attack on the house of a police officer in the port city of Karachi on Monday morning, which killed six police guards, a mother and her 12-year-old son.

The bomber rammed his explosives-laden car into the house of the Senior Superintendent Police of the Crime Investigation Department (CID), Chaudhry Mohammad Aslam, at Defense locality in Karachi.

Aslam, who escaped unhurt in the attack, told reporters that he had received threats from the Pakistani Taliban and other extremist groups. He said his police guards and the people working in his house were killed and injured.

Police sources said that CID had arrested several Taliban militants and members of other banned extremist groups in Karachi and its officials are under threats by the militant groups.

"I have received threatening letters from the banned Tehrik-e- Taliban Pakistan (TTP) and other terrorist groups but I did not know they would target my children while they were asleep," Aslam said. He said the attack was so brutal that even children became a target.

City Police Chief Saud Mirza told reporters that over 300 kilograms of explosives were used in the attack.

Mirza said that the CID officer had arrested several Taliban suspects in Karachi and he had been interrogating those suspects and this is the main reason the militants had attacked his house. He said the security agencies had been on high alert about any possible attack in Karachi.

Moeen Khan, a former captain of Pakistani Cricket Team, who lives in the area, told Geo television that the blast woke him up and when he arrived at the scene he saw dead bodies and injured pople lying on the street. He said the blast blew up fiber glass roofs of several nearby buildings including schools.

"I saw debris of the destroyed in 100 meters area and it was a terrible scene," Khan said, adding that there could be more deaths if the nearby schools had been opened.

Geo television reported that TTP claimed responsibility for the suicide blast and said it will keep on attacks to target the police officers.

TV channels said that some family members of the police officer were among the injured who were shifted to hospitals. But there was no official confirmation.

TV footage showed the destroyed house of the police officer and several destroyed vehicles. The attack also caused damage to nearby houses and schools.

Teams of the bomb disposal squad also arrived at the site and collected evidence. The blast created a 8-feet crater in the area, witnesses said.

Paramilitary troops and police cordoned off the attack site and security officials were seen collecting evidence.