A suicide bomber blew himself up in an SUV at a volleyball game in northwest Pakistan on Friday, killing at least 89 people in a village that opposes Al-Qaeda-linked Taliban insurgents, police said. The New Year's Day carnage suggests militants are focusing more on attacks on crowded civilian areas to inflict the most casualties and spread fear and chaos. Here are some questions and answers about militant groups in Pakistan, a nuclear-armed US ally. Who are the Pakistani Taliban? Most Pakistani Taliban fighters are ethnic Pashtuns from northwestern regions on the Afghan border. They support the Afghan Taliban, most of whom are also Pashtun and many of whom fled to the Pakistani Pashtun lands after US-led forces ousted Afghanistan's hardline Taliban government in late 2001. More than a dozen factions based in different parts of northwest Pakistan formed a loose umbrella group, the Tehrik-e-Taliban Pakistan (TTP), or Taliban Movement of Pakistan, led by Baitullah Mehsud in late 2007. Mehsud was killed by a missile-firing US drone aircraft in South Waziristan in August. He was replaced by Hakimullah Mehsud, seen as far more brutal. Mehsud is a Pashtun tribal name used by many members of the tribe as a last name. Baitullah Mehsud was accused of plotting numerous bomb attacks after the army stormed Islamabad's Red Mosque in 2007 to crush a militant movement there. But it was when the government named him the chief suspect in the assassination of former prime minister Benazir Bhutto in 2007 that his notoriety rocketed. Another key Pakistan Taliban leader is Fazlullah, known as the FM Mullah for spreading his radical views through radio airways in his former Swat Valley stronghold. He is believed to be guiding his supporters from Afghanistan. While many senior Taliban are veterans of Afghan fighting, they have exploited poverty, frustration over an ineffective judiciary, anger against landlords and widespread anti-US feeling to attract recruits. Can the military win? Judging by similar conflicts in other Muslim countries, such as Afghanistan, the battle could drag on for years. In mid-October, army troops launched a major offensive against the Taliban stronghold of South Waziristan. Militants struck back with bombings, killing hundreds across Pakistan, including a brazen attack on a mosque near army headquarters. Security analysts say Taliban fighters can simply flee one area to another across rugged mountain terrain the military has difficulty penetrating. Are the Pakistani Taliban linked to Al-Qaeda? Intelligence officials and security experts say they have grown increasingly close to Al-Qaeda. Baitullah Mehsud gave refuge to many foreign militants, including Arabs and Central Asians. While helping Al-Qaeda, he and his successor focused their attacks on Pakistan and its security forces. What is the relationship with the Afghan Taliban? The TTP swears allegiance to Mullah Omar, the chief of the Taliban in Afghanistan, and sends fighters across the border to Afghanistan. The Afghan Taliban are fighting what they call Western occupation forces. Some militant factions oppose violence in Pakistan and want all Taliban to focus on Afghanistan. But leaders such as the Mehsuds argue fighting Pakistani forces is justified because of Islamabad's support for the US-led campaign against Al-Qaeda and the Afghan Taliban. Three major Taliban commanders on the border are Maulvi Nazir Wazir, Hafiz Gul Bahadaur and Jalaluddin Haqqani, although the latter is elderly and his son Sirajuddin commands his fighters. Those figures are not in the TTP and are known for attacks in Afghanistan, not in Pakistan.