World leaders attending the Group of 20 annual summit in Buenos Aires on Saturday endorsed a "rules-based international order" in a joint final statement which also laid bare stark differences between key powers. 

The leaders pledged to create better jobs, tackle the sources of refugee movements and implement the "necessary reform" of the World Trade Organization (WTO) - a key demand of the United States.

"The system is currently falling short of its objectives and there is room for improvement," the joint statement said on multilateral trade mechanisms. 

"For the first time ever, the G20 recognized that the WTO is currently falling short of meeting its objectives and that it’s in need of reform," a US administration official said after Saturday's statement was issued. 

The document lacked any language against protectionist trade measures. The leaders were also split over climate change and migration.

But for host Argentina, the fact that a deal was reached was a success, given current tensions. The trade stand-off between China and the US meant an Asia-Pacific Economic Cooperation (APEC) summit last month was unable to produce a joint communique for the first time.

However, hours after the summit and following a highly anticipated dinner between US President Donald Trump and Chinise President Xi Jingping, the US and China announced a 90-day ceasefire in their months-long trade war.

The two sides said that tariffs on 200 billion dollars worth of Chinese goods would not be raised on January 1, as Trump had threatened.

However the White House warned that if a deal could not be reached in the 90-day timeframe on issues including forced technology transfer and intellectual property theft, the tariffs would go up.

It said China had also agreed to increase its imports from the US to reduce the trade imbalance between the two countries.

The US has also slapped tariffs on its traditional transatlantic and North American allies since Trump became president. Trump insists they are a reaction to years of unfair treatment and says he can reach better trade deals.

The US president also regularly takes aim at the Geneva-based WTO.

Teams from the G20 members laboured for a week to reach Saturday's agreement between the member states and had to ditch more concrete language on refugees, migration and climate change.

A separate paragraph in the joint leader's statement noted that the US had withdrawn from the 2015 Paris agreement, while other nations said they would continue to work for the deal's "full implementation." 

The US says the Paris deal is "job killing" and Trump has also voiced scepticism about the validity of scientific warnings about climate change. 

Trump cancelled a planned press conference in Buenos Aires, citing the death of former US president George HW Bush.

The summit saw a focus on one-on-one meetings, highlighting how the G20 forum has shifted to a venue offering world leaders a chance to meet, as multilateralism has moved onto the back burner.

The next G20 summit is due to take place in Japan in June.