King Salman of Saudi Arabia, right, welcomes Qatar's Emir Sheikh Tamim bin Hamad Al-Thani upon his arrival to Riyadh Airbase before the opening of Gulf Cooperation Council summit in Riyadh, Saudi Arabia, May 5, 2015. (Saudi Press Agency/AP)

Saudi, Qatar Relationship Worsens, Leaving OPEC Deal & Oil Price Stability At Risk

The cohesion of the Gulf Cooperation Council (GCC), which includes all Arab Gulf countries, seems to be cracking.