Diplomats from the BRICS group of developing nations have agreed on a joint declaration of their leaders at a summit in Rio de Janeiro this week, three people familiar with the talks said on Saturday.

BRICS leaders set to discuss key global political issues in Rio de Janeiro, but questions over the bloc’s cohesion arise as Chinese President Xi Jinping and Russian President Vladimir Putin opt to skip the summit.

BRICS leaders descended on sunny Rio de Janeiro Sunday, ready to issue a dark warning that US President Donald Trump's "indiscriminate" import tariffs risk hurting the global economy.