The G20 leaders' summit in Osaka comes at a critical moment for Trudeau, months ahead of the October election and as Canada continues to push for the release of two Canadians in China's custody -- Michael Kovrig and Michael Spavor.

Trump and Xi are due to sit down for dinner at the end of the G20 summit in Buenos Aires.

Turkish President Tayyip Erdogan said on Monday he had urged world powers at a G20 meeting to set up a "safe zone" in Syria where there would be no fighting.