ISLAMABAD - Pakistan's cities are unsafe from Islamist militant attacks due to their porous security, the country's defence minister said after suicide bombers and gunmen killed 11 people in an assault on a court in the capital earlier this week.
Carried out by a splinter group of the Paksitani Taliban, the attack will complicate the government's efforts to open peace talks as it destroyed trust on all sides, Defence Minister Khawaja Asif told Reuters.
"It is scary," Asif said in the wake of the worst attack in Islamabad since the bombing of the Marriott Hotel in 2008.
Responsibility for Monday's attack was claimed by a group called Ahrar-ul-Hind, or "Liberators of India", that had splintered from the Pakistani Taliban just a month earlier.
Coming a little over a week after the Pakistani Taliban announced a ceasefire to revive faltering peace talks with the Prime Minister Sharif's government, the attack may have succeeded in destroying chances for negotiation.
"Whatever little trust there was between the two parties, that trust has completely fizzled away," the defence minister said.
Frighteningly for Pakistan, investigators believe the leader of Ahrar-ul-Hind, Umar Qasmi, can draw support from other militant outfits, including several linked to al Qaeda, that have wreaked bloody havoc in the country over the last decade.
The three fighters who carried out Monday's attack were armed with hand grenades and automatic guns. Two died when they detonated suicide bombs, while a third escaped, officials say. Independent accounts say there were more gunmen.
It showed just how vulnerable the capital remains despite having almost as many security checkposts as traffic lights.
Last month, the national crisis management cell of the interior ministry made a presentation before parliament in which it described Islamabad as extremely dangerous, with sleeper cells of various militants groups lurking in the capital.
"Despite the fact that we have been fighting for the last many, many years now, we are ill-prepared to fight this war and to keep the major cities really safe," Asif said.
Investigators say Qasmi, a 38-year-old from the central province of Punjab, is experienced in organising joint operations against Pakistani cities, using fighters drawn from the country's Punjabi heartland and tribal lands bordering Afghanistan.
"Ahrar-ul-Hind could be the new name of one of several Punjabi factions that Taliban insurgents have teamed up with," said one official involved in investigating Monday's attack.
"A team of Pashto-speaking Punjabi fighters was carefully selected and given their target via a phone call," said a second investigator. "The fighters just had five days to study the building, rehearse the attack and strike. That was all it took."
Among those killed was a judge who ruled in October that former President Pervez Musharraf should not be tried for murder for ordering his commandoes to storm Islamabad's "Red Mosque" in 2007 to root out militants attempting to impose Islamic sharia in the capital.
The Pakistani Taliban are fighting to destroy Pakistan's fragile democracy and set up an Islamic sharia state, but had lately shown a readiness to talk as their strongholds in the northwest tribal lands bordering Afghanistan were targeted by military airstrikes over the past month.
Groups have broken off from the Pakistani Taliban before and many security analysts question whether this might be yet another ploy by the militants to gain the upper hand in negotiations by continuing terror attacks under another guise.
Announcing its formation in February, Ahrar-ul-Hind said it wanted no part of any ceasefire, and its attack has laid bare the Pakistani Taliban central leadership's lack of control over wilder elements operating on its fringes.
It is telling that militants whose ultimate dream was to fight India have now declared war on Pakistan. The nuclear armed rivals don't often share a common enemy when it comes to Islamist militants.
Critics say Pakistan is paying the price for its intelligence agencies' past and present policies of patronising militant groups to fight proxy wars in neighbouring India and Afghanistan.
Over the past decade, increasing numbers of Pakistani militants, angered by the presence of US forces in Afghanistan and enthralled by al Qaeda's anti-Western world view, have turned against a government and military that compromised by allying with the United States.
Intelligence officials say the new group has roots in the central province of Punjab bordering India.
Hatred of India is in the DNA of many Punjabi militants recruited by radical Islamist preachers to fight a jihad, or holy war, on the Indian side of Kashmir, the Himalayan territory disputed by South Asian rivals.
Pakistan's spy agency, the Directorate for Inter-Services Intelligence, has long tolerated - critics say backed - groups like Lashkar-e-Taiba and Jaish-e-Mohammad that target India.
According to intelligence officers, Qasmi hails from Jhang, a southern Punjab city that is home to the eponymous Lashkar-e-Jhangvi, an anti-Shi'ite sectarian group which supplied foot-soldiers for al Qaeda in Pakistan.
Soon after high school, they said, Qasmi moved to nearby Bahawalpur, close to the Indian border, where he is said to have enrolled in a seminary run by Maulana Masood Azhar, the head of Jaish.
And in subsequent years he became dangerously well-networked as he moved between southern Punjab and the tribal lands in the northwest, notably in the Mohmand region, where a Pakistani Taliban faction executed 23 soldiers last month - an incident that raised criticism of Sharif for pursuing peace talks.
Officials also believe Qasmi is close to Jundullah, the group behind a suicide bombing that killed at least 78 Christians at a church in Peshawar last September.
And they reckon he could muster 1,200 fighters drawn from various Punjabi-based groups for deadly operations against Pakistani cities.
"We belong to the urban areas of Pakistan," said Ahrar-ul-Hind spokesman Asad Mansoor. "The focus of our jihad activities will also be the urban areas."