XIAMEN, China (Reuters) - Chinese President Xi Jinping on Tuesday urged BRICS nations to deepen coordination on global matters, and push for a more "just" world order, by boosting representation for emerging and developing countries in international bodies.

Reiterating that emerging and developing markets have been the primary engine of global growth, Xi called for a bigger role for BRICS in speeding economic governance reforms and promoting trade, especially as rising risks veil a global recovery.

"BRICS countries should push for a more just and reasonable international order," Xi told a summit of the grouping, which includes Brazil, Russia, India, China and South Africa.

"We should work together to address global challenges."

In his closing remarks, Xi urged the grouping to battle for more "representation power" for emerging and developing countries, which some analysts say are often under-represented in global institutions such as the World Bank, by comparison with the dominance of the United States and Western Europe.

The summit in the southeastern city of Xiamen has given host China its latest chance to position itself as a bulwark of globalisation in the face of U.S. President Donald Trump's "America First" agenda.

Xi appeared to rebuke the United States's resistance to international pacts - including the Paris climate accord - in a separate speech earlier on Tuesday to leaders of BRICS and other developing countries.

"Multilateral trade negotiations make progress only with great difficulty and the implementation of the Paris Agreement has met with resistance," Xi said.

"Some countries have become more inward-looking, and their desire to participate in global development cooperation has decreased."

In talks on the North American Free Trade Agreement (NAFTA), Trump has sought improved terms for the United States, under threat of leaving the pact, and has said he will withdraw his country from the Paris climate accord.

Xi gave $500 million for a South-South cooperation fund to help other developing countries tackle famine, refugees, climate change and public health challenges, besides an earlier $80-million summit pledge to support BRICS cooperation.

Egypt, Guinea, Tajikistan, Thailand and Mexico joined the three-day summit as observer nations, and Xi called for a "BRICS Plus" plan to potentially expand the bloc, although no new member has been formally announced.

Xi lauded smooth progress in the grouping's cooperation in areas such as anti-terrorism and internet security.

"Leaders from the BRICS countries are determined to work towards another 'golden decade'," he added.

(Reporting by Michael Martina and Yawen Chen; Writing by Elias Glenn; Editing by Eric Meijer and Clarence Fernandez)