Intelligence and security agencies have carried out raids in several cities in Pakistan — in Lahore, Faisalabad and Multan —arresting an unspecified number of suspects, according to military spokesman Asim Bajwa. Bajwa added in a tweet: “Several suspected terrorists or those assisting them were arrested and a large cache of weapons and ammunition was seized.” Jamaat-ul Ahrar, a splinter group of the Pakistani Taliban that has sworn allegiance to the Islamic State (IS) group, claimed responsibility for the attack, promising “more similar attacks”, according to its spokesman, Ihsanullah Ihsan. This appears to be part of a covert struggle between IS and the Taliban for the hearts and minds of Pakistani extremists. Jamaat-ul Ahrar has claimed responsibility for several major attacks since it split from the Taliban in 2014, before announcing its return to its mother group. Markets, schools, courts and most businesses in Lahore shut down Monday to mourn the Christian victims. Christians make up just two per cent of Pakistan's 200 million citizens, the vast majority of which is Muslim. Although non-Muslims — Hindus, Christians and Ahmadis — constitute less than five per cent of the population in Pakistan, the major division in the country is between the Sunni majority and the 20 per cent of Pakistanis who are Shia. At least 70 people were killed in the suicide attack, including 29 children, seven women and 34 men; 341 people were injured, 25 of them critically, according to the Lahore paramedic authority. This attack is not the first on Christians, the vast majority of whom belong to the poor working and lower-middle classes, although some Christians have reached high office, such as A R Cornelius, the country's first non-Muslim chief justice. In September 2013, the Taliban claimed responsibility for suicide attacks on worshippers leaving a church in Lahore. That attack killed 82 people. In March 2015, 17 people were killed and 78 injured in a double suicide bombing against churches in Peshawar, the biggest city in the Federally Administered Tribal Areas (FATA) of northwest Pakistan, a stronghold of Taliban extremists. Since 2002, Christians have been targeted in nine major attacks that have killed hundreds. They have also been subject to prosecution under the country's blasphemy law, with many Christians accused of defaming the Prophet Mohamed or the Quran. Quoting eyewitnesses and workers in Iqbal Park, where the attack took place, Reuters and CNN reported that security measures were weak and there were few policemen in sight. Amir Jawad, a writer in the widely circulated Dawn newspaper, said that security measures had declined markedly when compared to the situation in 2010 and 2011. Pakistani security forces have often been accused of sheltering militants to use them in external conflicts in Afghanistan and against their longtime foe India in the disputed Kashmir region. “That was the situation until a few short years ago,” Jawad wrote. “But now there is a political and security awareness that these militants have become a burden on all of Pakistan.” Jawad continued: “This awareness is not limited to the authorities and security establishment, but extends to the media itself. A few years ago, there might not have been much sympathy for non-Sunni Muslim terrorist victims, like Shia, Ahmadis, Christians and Hindus, but now it is different. We hear journalists saying in the newsroom, ‘Why are they targeting these poor Christians?'” But regardless of the internal situation in Pakistan, which faces terrorism from a large number of militant groups, internationally Pakistan remains a major source of concern. According to a 2015 report from the Carnegie Centre, Pakistan is developing its nuclear arsenal more rapidly than any other country in the world. Islamabad currently has 100 to 120 nuclear warheads, more than its bitter enemy India. It is expected to surpass China, Britain and France by 2025, with an arsenal of 350 warheads. Most of this arsenal is composed of tactical weapons that can inflict battlefield damage and can be transported inside crowded cities. The nightmare scenario is that one of these weapons could fall into the hands of one of the many extremist groups operating in Pakistan. The world still remembers with alarm when the Pakistani Taliban came within less than 100 miles of Pakistani nuclear reactors in 2010. Nevertheless, the endemic factionalism within the Pakistani Taliban, the biggest militant group in the country, offers hope that the nightmare scenario that the Carnegie Centre has warned of will not come to pass. Due to successive security strikes by the Pakistani army, police and security, the Pakistani Taliban has been critically weakened. Successive strikes on the movement's leaders since 2009 have also served to direct their efforts to internal conflicts. The security services killed the first Pakistani Taliban leader, Baitullah Mehsud, in 2009, followed by Hakimulllah Mehsud in 2011. Most recently, the group has been riven by conflict following Mullah Fazlullah's assumption of leadership of the movement in 2012. But the question remains: Can Pakistan defeat extremist groups? It will not be easy, Jawad notes, since these groups are centred in impenetrable areas in the FATA region on the border with Afghanistan. Moreover, pressure from religious forces, which led to partition between Pakistan and India, remains strong. There are other factors as well, such as the conflict with New Delhi in Kashmir and the arms race in Southeast Asia. Sunni-Shia sectarian tension in the Islamic world also feeds extremism. Pakistan continues to suffer economically. More than 100 million people live in poverty and are thus vulnerable to religious groups, especially in areas where these groups provide social services such as health and education, which is typically religiously oriented.