US Treasury Secretary Steven Mnuchin announced the designations yesterday during a speech at an investment conference in the capital, Riyadh.
Saudi Arabia, Qatar, the United Arab Emirates, Oman, Kuwait and Bahrain jointly agreed to the sanctions list with Washington in what Mnuchin describes as "the largest ever multilateral designation in the Middle East."
The announcement represents a rare moment of coordination among the oil-rich Gulf states nearly four months after Saudi Arabia, the UAE and Bahrain, along with Egypt, severed ties with Qatar over its foreign policies.