HANGZHOU: G20 Summit leaders pose for a group photo in Hangzhou yesterday. —AP

HANGZHOU, China: Chinese President Xi Jinping urged world leaders to avoid "empty talk" and confront sluggish economic growth and rising protectionism as their summit opened yesterday in the scenic city of Hangzhou.

Xi welcomed Group of 20 presidents and prime ministers with a handshake, and an extended clasp with Barack Obama, as both men smiled despite protocol stumbles around the US leader's visit.

The Chinese leader said the world economy "still faces multiple risks and challenges including a lack of growth momentum and consumption, turbulent financial markets, receding global trade and investment". The rise of protectionism is challenging economic globalization, imperilling multilateral trade arrangements, and despite regulatory reforms market volatility is gathering pace, he said.

"We hope the Hangzhou summit will come up with a prescription for the world economy and lead it back to the road of strong, balanced, comprehensive and sustainable growth," Xi said.

The G20 brings together representatives of 85 percent of the world's GDP and two-thirds of its population. But experts fear the gathering will be short on substance, with no acute crisis pushing leaders to defy rising populist sentiment and to take difficult steps such as liberalizing trade.

In a circular conference hall in Hangzhou-the eastern city left deserted by a vast security operation-Xi told leaders the G20 "should work with real action, with no empty talk". China is hoping a successful meeting will portray it as an assured and powerful nation ready to assume a role on the international stage that befits its status as the world's second-largest economy.

Authorities shut thousands of factories to try to clear the skies of smog, and encouraged residents to leave town on free holidays, as well as detaining dozens of dissidents to prevent any hint of unrest.

No deal on Syria

The summit was preceded by a flurry of diplomatic activity on issues ranging from climate change and the war in Syria to international trade. The US and China on Saturday ratified the Paris climate accord, a crucial step towards bringing into force the pact against global warming. There had been hopes for another breakthrough, on the long war in Syria, after the US said it was close to a deal with Russia on stemming the violence.

But negotiations between Secretary of State John Kerry and his counterpart Sergei Lavrov yielded only an agreement to convene again on Monday, with Russia accused of "walking back" on key issues. Moscow and Washington support opposite sides in the conflict, which erupted in March 2011 after President Bashar Al-Assad unleashed a brutal crackdown on a pro-democracy revolt.

Successive rounds of international negotiations have failed to end a conflict that has left more than 290,000 people dead and forced millions to flee, a key contributor to migrant flows into Europe.

EU President Donald Tusk said Europe was "close to limits" on its ability to accept new waves of refugees and urged the broader international community to shoulder its share of the burden. The issue has become a political hot potato for European leaders as Islamist terror attacks and rising anti-globalization sentiment fuel public resentment of immigration.

Pictures of a drowned three-year-old Syrian boy lying on a Greek beach briefly changed the discourse last year, with Germany throwing open its borders, but a major backlash swiftly followed.

Ahead of the summit, Canadian Prime Minister Justin Trudeau warned against "rampant" protectionism and nationalism, saying that "building walls" was not the solution." The talks are being held in the wake of Britain's vote to leave the European Union, which leaves it with the task of renegotiating access to the markets of the rest of the world. It is a huge job for the world's fifth-biggest economy, and Australian Prime Minister Malcolm Turnbull said Canberra had "got things moving towards having a free trade agreement with the UK".

But European Commission chief Jean-Claude Juncker said he opposes such talks while Britain remains part of the EU, insisting they were an "exclusive matter" for the bloc on behalf of its members and "we are sticking to it".

No fast-track post-Brexit deal

US President Barack Obama offered Britain little hope of a fast-track post-Brexit trade deal yesterday, but said he would work to ensure the economic relationship between the two does not unravel after the British vote to leave the European Union.

Obama met with British Prime Minister Theresa May at the start of a G20 summit in China as Britain embarks on the long process of reinventing itself as an independent trading nation following the shock June EU referendum outcome.

Obama, who in April used a visit to London to tell Britain it would be at the back of the queue for a trade deal if it left the EU, met with May for the first time since she became prime minister to discuss Brexit and other global challenges. He offered May reassurance that Britain's closest political, commercial and military ally would stand by her, but did not shrink away from his stance that Brexit was a mistake and that London would not be able to jump the queue to arrange a bilateral deal.

"It is absolutely true that I believed pre-Brexit vote, and continued to believe post-Brexit vote, that the world benefited enormously from the United Kingdom's participation in the EU,"he said.

"First things first - the first task (for Britain) is going to be figuring out what Brexit means with respect to Europe, and our first task is making sure we get, first, TPP (Trans-Pacific Partnership) done and also that we move forward on the TTIP (Transatlantic Trade and Investment Partnership) negotiations in which we've invested a lot of time and effort." TTIP is a stalled US-EU trade deal, while TPP is Obama's signature Asian trade deal. - Agencies