The Islamic State (IS) is targeting the Sunni-Shiite sectarian divide in Saudi Arabia to create discord and undermine the royal family's rule. The kingdom is vulnerable to sectarian strife given the family's intimate connections to the Wahhabi Sunni clerical establishment, years of suppression of Shiite Saudis and the war in Yemen.
The first IS terrorist attack on Saudi Shiites took place in November. This month there have been two suicide attacks on Shiite mosques on successive Fridays. The first killed 21 worshippers inside a mosque, the second bomber was stopped outside the mosque before blowing himself up, killing four.