Leaders of the Brics group of developing nations condemned attacks on Iran, Gaza and Kashmir during their summit on Sunday, presenting the bloc as a defender of multilateral diplomacy while indirectly criticising US military and trade policy.

With forums such as the G7 and G20 groups of major economies hamstrung by divisions and the disruptive "America First" approach of US President Donald Trump, expansion of the Brics has opened new space for diplomatic coordination.

In his opening remarks at the meeting in Rio de Janeiro, Brazilian President Luiz Inacio Lula da Silva drew a parallel with the Cold War's Non-Aligned Movement, a group of developing nations that resisted joining either side of a polarised global order.

"Brics is the heir to the Non-Aligned Movement," Lula told leaders. "With multilateralism under attack, our autonomy is in check once again."

Brics nations now represent more than half the world's population and 40 percent of its economic output, Lula noted in remarks on Saturday to business leaders warning of rising protectionism.

The original Brics group gathered leaders from Brazil, Russia, India and China at its first summit in 2009.

The bloc later added South Africa and last year included Egypt, Ethiopia, Indonesia, Iran, Saudi Arabia and the United Arab Emirates as members.

This is the first summit of leaders to include Indonesia. (Reuters)