Taliban Claim Deadly Attack on Pakistani Spy Agency ISLAMABAD, Pakistan - Taliban militants claimed responsibility on Thursday for an attack on a regional office of Pakistan's main spy agency that left at least nine people dead and again highlighted the militants" ability to strike sensitive targets. Four attackers struck an office of the military's Inter-Services Intelligence Directorate on Wednesday night in Sukkur, a town in the southern province of Sindh. Masood Ahmed Bangash, a senior police officer in Sukkur, said the attack struck as people were ending their daily fast, as part of the holy month of Ramadan. A suicide bomber blew up a vehicle outside the ISI compound, and was followed by three gunmen who attacked security forces and police officers inside. All three were killed in the course of a firefight that lasted roughly half an hour. Five other people, including at least one civilian official with the intelligence agency, and three security force personnel also died in the attack. Militant bombers have targeted the ISI several times in the past six years. Five people were killed in an attack on an agency office in Faisalabad, in Punjab Province, in 2011. At least 23 people died in an attack on the ISI regional headquarters in Lahore in 2009. The attacks show how some jihadi factions that were once nurtured by Pakistani intelligence have turned on their former handlers. But such attacks have been rare of late, and the meticulous nature of Wednesday's assault showed the strength of the militants" reach despite near-continuous military operations against their tribal strongholds along the Afghan border. Competing claims of responsibility for the attack, however, left it unclear which Taliban faction was responsible for the attack. On Thursday, one commander with the main group, known as Tehreek-e-Taliban Pakistan, said his group had carried out the attack. But a representative of what appears to be a Taliban splinter faction, known as Jundullah, also claimed responsibility for the attack. The spokesman said it was in retaliation for an American drone strike that killed the Taliban's deputy leader, Wali ur-Rehman, in May. The confusion partly stems from the fact that the Taliban's central spokesman, known as Ehsanullah Ehsan, was fired in early July. His replacement, Sheikh Maqbool, has yet to assume his duties. A Pakistani security official, speaking on the condition of anonymity, said the attack was most likely a reaction to a continuing crackdown against militants in Punjab Province and in Karachi, the southern port city. Pakistani law enforcement officials have recently arrested dozens of militants, mostly belonging to banned sectarian groups, in the Faisalabad and Jhang districts of Punjab, as well as in Karachi. "The noose around the militants is tightening," the official said. Obviously, they would retaliate.