Security forces stand guard in downtown Buenos Aires, on November 30, 2018, on the first day of the G20 Leaders' Summit. (AFP)

Mexico's President Enrique Pena Nieto (L) US President Donald Trump (C) and Canadian Prime Minister Justin Trudeau, sign a new free trade agreement in Buenos Aires, on November 30, 2018, on the sidelines of the G20 Leaders' Summit. (AFP)

Participants of the G20 Leaders' Summit in Buenos Aires, pose for the family photo on November 30, 2018. (AFP)

Managing Director of the International Monetary Fund (IMF) Christine Lagarde (L) is welcomed by Argentina's President Mauricio Macri at Costa Salguero in Buenos Aires during the G20 Leaders' Summit, on November 30, 2018. (AFP)

US President Donald Trump and Argentina's President Mauricio Macri meet before the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. 2018. (Reuters)

Russian President Vladimir Putin and Saudi Crown Prince Mohammed bin Salman attend the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. (Reuters)

US President Donald Trump and Britain's Prime Minister Theresa May attend the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. (Reuters)

Chinese President Xi Jinping attends the opening of the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. (Reuters)

Russia's President Vladimir Putin and Saudi Arabia's Crown Prince Mohammed bin Salman prepare for a family photo during the G20 summit in Buenos Aires, Argentina November 30, 2018.(Reuters)

Turkey's President Recep Tayyip Erdogan arrives at Costa Salguero in Buenos Aires to attend the G20 Leaders' Summit, on November 30, 2018. (AFP)

Turkish first lady Emine Erdogan, Canada's Prime Minister Justin Trudeau's spouse Sophie Gregoire Trudeau, Chinese President Xi Jinping' spouse Peng Liyuan, Argentina's first lady Juliana Awada, US first lady Melania Trump, Singapore's Prime Minister Lee Hsien Loong's spouse Ho Ching, European Council President Donald Tusk's spouse Malgorzata Tusk, French first lady Brigitte Macron, Japanese Prime Minister Shinzo Abe's spouse Akie Abe, South Korea's first lady Kim Jung-sook, pose for a family photo as they visit at the Villa Ocampo museum during the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. (AFP)

The limousine carrying US President Donald Trump arrives for the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. (Reuters)

Mexico's President Enrique Pena Nieto waves as he arrives last to the family photo of the G20 Leader's Summit at the Costa Salguero Center in Buenos Aires, Argentina, Friday, Nov. 30, 2018. (AP)