Chinese President Xi Jinping and other leaders from the BRICS group - Brazil, Russia, India, China and South Africa - issued a statement urging open international trade and a strengthening of the World Trade Organization (WTO).
"The spirit and rules of the WTO run counter to unilateral and protectionist measures," they said in the statement. "We call on all members to oppose such WTO-inconsistent measures, stand by their commitments undertaken in the WTO."
The Buenos Aires summit comes amid the trade war between the US and China, the world's two largest economies, which have imposed tariffs on hundreds of billions of dollars’ worth of each other's imports after US President Donald Trump initiated a measure to fix what he regards as Beijing’s unfair commercial practices, Presstv Reported.
China hopes for breakthrough in US tariffs
This is while Chinese officials at the summit hope to persuade Trump to abandon plans to raise tariffs on $200 billion of Chinese products to 25 percent in January, from the current rate of 10 percent.
"We're working very hard. If we could make a deal that would be good. I think they want to. I think we'd like to. We'll see," Trump asserted.
A Chinese foreign ministry official in Buenos Aires emphasized that there were signs of growing consensus ahead of the discussions, although differences remained.
With a rise in nationalist sentiment in many countries, the G20 - which accounts for two-thirds of the global population - faces challenges over its ability to deal with trade tensions, which have shaken global markets.
Meanwhile on the eve of the summit, G20 nations were still struggling to reach consensus on the wording for the summit's communique on major issues -- such as trade, migration and climate change -- which in past years have been worked out well in advance.
While Argentina's president voiced cautious optimism that consensus would be reached, a White House official was cited in press reports as saying that Washington would walk away from any statement that prejudiced American interests.
Summit's communique urges multilateral trading
A communique was eventually issued on Saturday after Brazilian President Michel Temer, Russian President Vladimir Putin, Indian Prime Minister Narendra Modi, Chinese President Xi Jinping and South African President Cyril Ramaphosa held an informal meeting on the sidelines of the summit on Friday.
According to the communique, BRICS countries agreed that full support should be given to the rules-based multilateral trading system represented by the WTO and to ensure transparent, non-discriminatory, open and inclusive international trade.
The document further urged all WTO members to oppose unilateral and protectionist measures that disaccord with WTO rules and withdraw such measures that are restrictive and discriminatory in their nature.
BRICS countries also vowed to back the improvement of the WTO, boost its relevance and validity and safeguard the core values and basic principles of the WTO, and agreed that the WTO should embody the interests of all members, developing economies in particular.
Also at the summit, Trump cited Russia's recent seizure of Ukrainian warships in its territorial waters as the reason he canceled a planned bilateral meeting with Russian President Vladimir Putin, where they had been expected to discuss Trump's threat to withdraw from the Cold War-era Intermediate-Range Nuclear Forces treaty (INF).
Moscow, however, insisted that US domestic politics were most likely the real reason behind the cancellation after Trump's former personal lawyer pleaded guilty on Thursday to lying to Congress about a proposed Trump Organization skyscraper in the Russian capital.
Putin has also weighed in, with a thinly veiled attack on his US counterpart’s America First policy, censuring Washington’s "dishonest competition" along with "vicious" sanctions and protectionist measures.
Meanwhile, there were massive security measures in place for the summit in Buenos Aires, with a bank holiday declared or Friday and the city's main business district shut down.
Local protesters angry at the money spent on the summit while Argentina struggles through tough austerity waged huge rallies outside the meeting’s venue.