Secretary-General of the Gulf Cooperation Council Abdurrahman bin Hamad Al Attiyah left Muscat this evening, wrapping up a two-day visit to Oman. Earlier, Sultan Qaboos bin Saeed of Oman met with the GCC Secretary General and discussed with him means of developing and enhancing GCC march in all domains as well as preparations underway for the upcoming 30th GCC leaders Supreme Council meeting in Kuwait, QNA (Qatar News Agency) reported.