Two Shia activists in the Gulf states have been stripped of their citizenship earlier this week, sparking claims of discrimination and pointing to growing tensions between Sunnis and Shias.
Kuwaiti activist Yasser al-Habeeb was accused of abusing religious symbols and trying to cause a sectarian rift. He had made disparaging remarks about the Prophet Muhammed's wife.
So worried is the Kuwaiti government at the possibility of violence that it has banned all public gatherings to try to contain the tensions.
In Bahrain, Ayatollah Hussein Mirza Najati was stripped of his passport on Sunday in a clamp-down on Shia activists ahead of next month's parliamentary elections.
Bahrain has seen a wave of clashes and street protests by Shias who form the majority of the population - but say they face discrimination in state jobs and housing.
Many fear that the differences between the two sides will increasingly come to the fore, sparking unrest in the region and determining regional alliances and political attitudes.
So, is the Sunni-Shia divide about to explode wide open?
Inside Story, with presenter Shiulie Gosh, discusses with Faleh Abdeljabbar, the director of the Iraqi Institute for Strategic Studies, Mehdi Hassan, the senior political editor of the New Statesman, a weekly current affairs and politics magazine, and Azzam Tamimi, the director of the Institute of Islamic Political Thought.
This episode of Inside Story aired from Tuesday, September 21, 2010.