"The State of Qatar has employed its ample financial resources to exert regional influence separate from and independent of Saudi Arabia, the de facto leader of the alliance of six Gulf monarchies called the Gulf Cooperation Council (GCC: Saudi Arabia, Kuwait, Qatar, United Arab Emirates, Bahrain, and Oman). Qatar has intervened in several regional conflicts, including in Syria and Libya, and has engaged both Sunni Islamist and Iran-backed Shiite groups in Lebanon, Sudan, the Gaza Strip, Iraq, and Afghanistan. Qatar has maintained consistent dialogue with Iran while also supporting U.S. and GCC efforts to limit Iran's regional influence. However, Qatar's independent policies, which include supporting regional Muslim Brotherhood organizations and establishing a global media network called Al Jazeera, have caused a backlash against Qatar by Saudi Arabia and some other GCC members. The GCC has been on the verge of dissolution since June 5, 2017, when Saudi Arabia, the UAE [United Arab Emirates], and Bahrain, joined by Egypt and a few other governments, severed relations with Qatar and imposed limits on the entry and transit of Qatari nationals and vessels in their territories, waters, and airspace."
CRS Report for Congress, R44533
Congressional Research Service: https://crsreports.congress.gov/