Leaders of Mexico, Egypt, Tajikistan, Guinea and Thailand were invited by China to sit at a roundtable with BRICS leaders.
Though outreach programs have existed in past BRICS summits since 2013, it was the first time the program had such an extensive representation - from almost every region of the world.
Xi said BRICS cooperation was more than about just five countries, but carried the expectation of the entire international community.
He had earlier used an idiom to sum up the mindset behind such partnerships: "One should help others as he establishes himself and bear the well-being of the world in mind."
Xi said BRICS leaders supported the "BRICS Plus" approach proposed by China to strengthen South-South cooperation.
People all over the world are beginning to realize the sheer potential of BRICS for cooperation among developing countries.
"BRICS is really going to shock people in terms of what is able to achieve," said South African businessman Iqbal Surve.
Xi called out to his colleagues: "Let us set sail from Xiamen and join hands to usher in the second 'golden decade' of BRICS cooperation."