The BRICS nations of Brazil, Russia, India, China and South Africa represent a quarter of the global economy, and interest in joining the group surged ahead of its three-day summit in Johannesburg.
Security has been bolstered across the city where South African President Cyril Ramaphosa is hosting China's President Xi Jinping, Indian Prime Minister Narendra Modi, Brazil's President Luiz Inacio Lula da Silva and some 50 other leaders.
Russian President Vladimir Putin, who is the target of an international arrest warrant over alleged war crimes in Ukraine, did not attend in person and addressed the summit via pre-recorded video.
Russia will be represented in Johannesburg by Foreign Minister Sergei Lavrov,
China is the BRICS most powerful economy and Xi's state visit to South Africa, just his second international trip this year, comes as Beijing pushes to rapidly expand the group's membership.
"Now as friends and BRICS partners, we stand together in our shared objective and quest for a better and more egalitarian world," said Ramaphosa in Pretoria at the opening of Xi's visit.