KARACHI - Twin blasts hit two buses carrying Pakistan Navy officials in Karachi Tuesday, killing four people. Nearly 60 people were wounded when two remote-controlled bombs exploded beside the Navy buses at rush hour in different parts of the city. The first blast took place in Defence Housing Society where a remote-controlled bomb fixed on a motorcycle bearing registration number (KAZ-7694) went off at around 7:32am and hit a Navy bus. As a result, two Navy personnel: Dr Shazia and Sub Lieutenant Muhammad Iqbal died on the spot while 25 others sustained injuries. The bodies and injured were rushed to PN Shifa Hospital. Following the blast, heavy contingents of police, Rangers, teams of various investigation agencies and officials of bomb disposal squad rushed to the spot and cordoned off the area. Within a span of 10 minutes, another bomb was exploded at Northern Bypass in the limits of Maripur police station. The bomb was dumped inside a garbage drum near Northern Bypass and blew up when another naval bus reached close to the place. Two people were killed and 35 others injured in the blast. Law enforcement agencies and other concerned officials were rushed to the spot and found another 10 kg bomb in the garbage drum and defused it. Iftikhar Tarar, DIG investigation, said the bombs were exploded with the help of mobile phones. He also said police have arrested Kamran Qureshi, owner of the motorbike used in the blast, while sources said Qureshi had sold his bike some two weeks ago. Police believed same group was behind the Monday blasts and the modus operandi of the blasts was similar to that of the Rummy Club explosion. Investigators suspect that Tehrik-e-Taliban Pakistan and Lashkar-e-Jhangvi are behind the blasts. According to bomb disposal squad officials, 4 kg explosive material was used in each bomb. Agencies add: The Taliban claimed responsibility for the attacks, and vowed more attacks on security forces. Security forces will be targeted in the future as well, because they are killing their own people in Waziristan and elsewhere at the behest of the United States, Taliban spokesman Ehsanullah Ehsan told Reuters by telephone from an undisclosed location. Attacks on security personnel are rare in Karachi. Officials said four people were killed in the attacks and the navy, which is based largely in Karachi, identified them all as its employees. The four dead were navy officials including a lady doctor, a sub lieutenant, a sailor and a civilian employee, navy spokesman Commander Salman Ali told AFP.