Co-operation in areas from politics and security to economics and finance is the grouping's main focus, with 2026 chair India and 2027 chair China seeking wider partnerships to boost its global clout.
The success of the "Greater BRICS Initiative" depends on laying a solid foundation for pragmatic co-operation, Xi told the leaders' annual summit in New Delhi on Sunday, the official Xinhua news agency said.
"Greater BRICS" nations should further co-operate, maintain the stability of industrial and supply chains, and cultivate an integrated market, Xi told the summit's closing session.
China will take the lead in establishing a BRICS AI Open Source Zone to promote co-operation on large language models, AI training and an open AI ecosystem, Xi said.
He also proposed a BRICS Special Economic Zone partnership and said China would host a BRICS Service Trade Forum in 2027 to boost trade and investment ties.
BRICS has expanded to include Iran, Indonesia, Egypt, Ethiopia and the United Arab Emirates beyond its original membership of Brazil, Russia, India, China and South Africa two decades ago, which aimed to transform a world order dominated by the US.
In addition, 10 partner countries span emerging economies across Asia, Africa, Latin America and the Middle East, broadening BRICS' reach across the Global South.
China and Russia sometimes refer to this larger bloc as "Greater BRICS".
The benefits of solutions developed within BRICS should not stay limited to BRICS alone, but should be adaptable and accessible to meet the needs of the Global South, Indian Prime Minister Narendra Modi said earlier.
Russian President Vladimir Putin called BRICS a powerful driving force towards creating a new, fairer and multipolar world order, urging its members to find ways to combine the competitive advantages of their individual economies.
The summit comes amid renewed fighting in the Gulf region, with tit-for-tat attacks by the US and Iran, and as Iran-backed Houthis widen the conflict by launching attacks on Saudi Arabia.
But the weekend summit scored an important diplomatic goal on Saturday, when it reached consensus on a joint declaration backed by Iran and the UAE.
In general terms, the declaration expressed deep concern over the continued escalation of tensions in the Middle East and urged maximum restraint.
Separately, Iranian President Masoud Pezeshkian also met the Crown Prince of Abu Dhabi on the sidelines, in the highest-level meeting of officials from the two countries since the start of the conflict.
They discussed de-escalation and stability and efforts to advance regional peace and development.
