Sectarian divisions increase in Syrian conflict
The conflict in Syria is increasingly fuelled by the sectarian divide between Sunni and Shia Islam in the region. Professor Mark Katz of the US's George Mason University explains what fuels the Sunni-Shia divide.
Syrian President Bashar al-Assad heads a secular regime but is a member of the Alawite sect, a branch of Shia Islam founded in Syria during the ninth century.
He relies on support from Iran and the Lebanese-based Hezbollah group.
The opposition has received millions of euros in financial and humanitarian aid from the Sunni kingdoms of Saudi Arabia and Qatar.
Over the past year an increasing number of hardline Sunni groups have entered the Syrian conflict with the express aim of ousting Assad and forming an Islamic state.
Chief among these groups is the Islamic State of Iraq and the Levant that is thought to be behind suicide bombings and kidnapping of foreigns.