Shia–Sunni relations
Shia–Sunni discord in Iraq starts with disagreement over the relative population of the two groups. According to most sources, including the CIA's "World Factbook", the majority of Iraqis are Shia Arab Muslims (60%-70%), and Sunni Arab Muslims represent between 32% and 37% of the population. However, Sunni are split ethnically among Arabs, Kurds and Turkmen. Many Sunnis hotly dispute their minority status, including ex-Iraqi Ambassador Faruq Ziada, and many believe Shia majority is "a myth spread by America". One Sunni belief shared by Jordan's King Abdullah as well as his then Defense Minister Shaalan is that Shia numbers in Iraq were inflated by Iranian Shias crossing the border. Shia scholar Vali Nasr believes the election turnout in summer and December 2005 confirmed a strong Shia majority in Iraq.
Sectarian violence among Muslims
Following the 2003 Invasion of Iraq and subsequent fall of Saddam Hussein's regime, the minority Sunni sect, which had previously enjoyed increased benefits under Saddam's rule, now found itself out of power as the Shia majority, suppressed under Saddam, sought to establish power. Such sectarian tensions resulted in a violent insurgency waged by different Sunni and Shia militant groups, such as al-Qaeda in Iraq and the Mahdi Army. Following the U.S. withdrawal in 2011, violence has increased to 2008 levels.
In February 2006, more than 100 people were killed across Iraq, when violence between the two Muslim rival sects erupted. It has left over a hundred people dead and dozens of mosques and homes destroyed.
The Grand Mufti of Saudi Arabia, Abdul-Aziz ibn Abdullah Al Shaykh, issued a fatwa on 12 September 2013 that suicide bombings are "great crimes" and bombers are "criminals who rush themselves to hell by their actions". Sheikh described suicide bombers as "robbed of their minds... who have been used (as tools) to destroy themselves and societies."