The Italian prime minister was due to meet the leaders of France, Germany and the UK before the main summit in a session seen as a European "huddle" created to present a united front to President Trump, who has imposed trade tariffs on the EU and disagrees with the bloc over a nuclear deal with Iran.
Russian Federation was suspended from the group - then known as the G8 - in 2014 after the majority of member countries allied against its annexation of Crimea.
Chinese President Xi Jinping said at the opening of the meeting of the SCO Council that the SCO has become even stronger after the accession of India and Pakistan, and it implies greater responsibility on its member states for ensuring stability, security and regional development.
He said a meeting could take place as soon as the United States was ready and that many European countries had offered their help in making it happen.
The show of unity was in stark contrast to the calamitous end to the Group of Seven meeting in Quebec City, after US President Donald Trump disowned a joint summit statement and lambasted Canadian Prime Minister Justin Trudeau as "dishonest" and "weak".
"Italy has been left on his own on this issue but we must have reforms and we want to see some more solidarity within Europe", he told Italian reporters. His remarks come a day after President Donald Trump proposed the inclusion of Russian Federation in the G7 Summit. On Xi's last visit to Moscow, in July 2017, Putin made him a member of the Order of St Andrew, Russia's highest chivalric order. Tensions mounted between the Trump administration and fellow G7 members Canada, Germany and France when the U.S. imposed steep tariffs on imported metals from the countries.
Putin emphasized the significance of the SCO, which includes Russian Federation and China, and said the combined purchasing power of the SCO was bigger than G7. "I think this is a very important step in building our relations".
That's why he sees it as such a great and brilliant victory that he pulled us out of a series of global agreements: the Trans-Pacific Partnership, the Paris Climate Accord, the Iran nuclear agreement. "The ball, I believe ..."
Speaking in La Malbaie, the small town in Quebec that hosted the weekend's summit, he said: "Why are we having a meeting without Russian Federation in the meeting?"
The China-Russia relations, standing at a high level, have benefited the two peoples and served as a model of harmonious coexistence of major countries and neighboring countries.
Former Obama administration national security adviser Susan Rice on Sunday called it "disgraceful" for President Donald Trump to blame his predecessor President Barack Obama for letting Russian Federation get away with its annexation of Crimea in 2014.