(Corrects final paragraph to remove reference to Lebanon as site of attacks) Jan 18 (Reuters) - At least 11 people died in a suicide bomb blast in a Shi'ite Muslim prayer hall in the Pakistani city of Peshawar on Thursday. The blast comes one day before the Ashura weekend, the Shi'ite calendar's biggest event, which has become a flashpoint for deadly attacks by Sunni militants over recent years. Here are some key facts about Ashura and frayed relations between Pakistan's Sunni and Shi'ite groups: WHAT IS ASHURA?: -- Ashura falls on the tenth day of a 40-day mourning period during the Islamic calendar's first month, Moharram, which commemorates the death of Imam Hussein, a grandson of the Prophet Mohammad, who was killed in battle in A.D. 680 in the Iraqi city of Kerbala. -- The schism between Sunnis and Shi'ites is rooted in a dispute over the successors of the Prophet following his death in A.D. 632. -- Sunnis regard Abu Bakr, one of Mohammad's companions, as his successor. Shi'ites revere Ali, the prophet's son-in-law and cousin. Ali was also the father of Hussein, whose death Ashura commemorates. -- Marching down streets, worshippers flog themselves with steel-tipped flails or slash their bodies with knives to express solidarity with Hussein. WHY IS THE FESTIVAL A FLASHPOINT FOR VIOLENCE?: -- The most important festival in the Shi'ite calendar, it draws thousands of people to streets in cities across Pakistan. -- Shi'ites make up about 15 percent of Pakistan's 160 million people. The overwhelming majority are Sunni Muslims. -- Security is usually upped in the days leading up to Ashura. But most attacks are carried out by suicide bombers that are almost impossible to stop. -- Last year, in the days leading up to Ashura, at least 17 people were killed in the space of just over a week. -- One of the worst Ashura attacks was in 2006, when about 40 people were killed in a suicide attack on a procession in the northwestern town of Hangu. During Ashura in 2003, at least 57 Shi'ites were killed in Quetta, the capital of the western province of Balochistan.-- Over the past three decades thousands of Pakistanis have died in feuding that sprang out of the radicalisation of the two sects as a result of the jihad, or holy war, covertly funded by the United States and Saudi Arabia, against the Soviet occupation of Afghanistan, and a revolution that turned Iran into a republic led by Shi'ite clerics. -- As well as Pakistan, there have been deadly attacks during Ashura in Iraq, which has a large Shi'ite population. Kerbala and Baghdad have seen bloody violence over the years. (Writing by Shahida Patail, Singapore Editorial Reference Unit)
Indian policemen detain a Kashmiri Shia Muslim during a Moharram procession in Srinagar January 18, 2008. Police used batons and detained dozens of Kashmiri Shia followers as they tried to take ...