The Group of 20 Leaders' Summit began yesterday in Buenos Aires, Argentina, against the backdrop of disagreements among major powers over issues such as trade and geopolitical flashpoints.
This year's summit is the 10th since the first one brought leaders of the world's 20 largest economies together during the global financial crisis. It is also the first to be held in South America.
With Argentina at the helm this year, the two-day global forum is set to focus on the future of work, infrastructure for development and a sustainable food future.
Argentinian President Mauricio Macri said in a summit publication: "Consensus is not always assured, but that is what the G-20 is for - to bring together the views of a diverse set of players to find common ground and commit to action for a shared and prosperous future."
The leaders arrived on Thurs-day, and the tensions were already apparent.
In tweets on Thursday afternoon, US President Donald Trump abruptly called off a planned meeting with Russian President Vladimir Putin over Russia's seizure of Ukrainian navy ships in disputed waters off the Crimean peninsula on Sunday.
Mr Trump said: "Based on the fact that the ships and sailors have not been returned to Ukraine from Russia, I have decided it would be best for all parties concerned to cancel my previously scheduled meeting in Argentina with President Vladimir Putin. I look forward to a meaningful summit again as soon as this situation is resolved!"
All eyes are also on a scheduled dinner today between Mr Trump and President Xi Jinping, which may determine whether US-China trade tensions abate or worsen towards the planned hike of US tariffs on all Chinese goods, which is due to take effect on Jan 1.
Mr Trump told reporters before departing the White House on Thursday: "I think we are very close to doing something with China, but I don't know that I want to do it."
Meanwhile, French President Emmanuel Macron hinted that he would raise the issue of the murder of Saudi journalist Jamal Khashoggi when he meets Saudi Crown Prince Mohammed bin Salman, whom the CIA reportedly concluded had ordered the killing.
"I will inevitably have the opportunity to discuss it with the Saudi Crown Prince on the sidelines of the G-20," Mr Macron said at a joint press conference in Buenos Aires on Thursday.
Prime Minister Lee Hsien Loong is attending the summit as Argentina has invited Singapore as chairman of Asean this year.
On Thursday, he met Buenos Aires Mayor Horaci Rodriguez Larreta and welcomed the growing ties between Singapore and the Argentinian capital.
Mr Larreta briefed him about his government's efforts to improve mobility by expanding the city's public transport networks and car-free zones.
PM Lee said Singapore and Buenos Aires would benefit from more exchanges of ideas on areas of mutual interest, and invited Mr Larreta to visit Singapore to learn more about Singapore's policies in security, urban development and Smart Nation programmes, said a statement from the Prime Minister's Office (PMO) on Thursday.
He also met Argentinian Senate president Federico Pinedo, Buenos Aires Senator Esteban Bullrich, Santa Fe national deputy Astrid Hummel, and other Argentinian Congress members.
PM Lee talked about Singapore's interest in strengthening ties between both countries' Parliaments and deepening links with Argentina's provinces, particularly Buenos Aires and Santa Fe, two of its most significant provincial economies.
Both sides discussed how to further cooperate in areas such as the promotion of trade and investment, agri-food exports, and educational exchanges, said the PMO.
PM Lee welcomed members of the Argentinian Congress to visit Singapore as part of a parliamentary exchange visit, while Speaker of Parliament Tan Chuan-Jin was invited to visit Argentina with fellow MPs.