By Dave Clark

LOS CABOS, Jun 17, 2012 (AFP) - The leaders of the world's most powerful economies meet Monday for a G20 summit confronted by turmoil in the eurozone, a critical election in Greece and worsening bloodshed in Syria.

Some 27 heads of state and government are to gather in the sun-drenched Mexican beach resort of Los Cabos for two days of meetings, but the trip is anything but an escape from the crises threatening the global order.

If Greece votes on Sunday to reject the terms of its debt bail-out, Europe's plan to save the euro will be thrown into disarray and Germany's Chancellor Angela Merkel will come under huge pressure to change course.

US President Barack Obama comes to Mexico knowing that, if the eurozone crisis continues to hurt global growth, America's already faltering economy could stumble, undermining his own hopes for reelection.

Obama also faces tense face-to-face talks in Los Cabos with his Russian opposite number Vladimir Putin, who is standing in the way of a united UN Security Council response to the worsening violence in Syria.

France's new president, Francois Hollande, will come to his first G20 in the aftermath of Sunday's legislative elections there, which will decide whether he has a working majority to develop his own response to the debt crisis.

The leaders will also be keeping an eye on developments in Egypt, the Middle East's most populous country, where constitutional wrangling has hurt hopes of democratic reform in the wake of the Arab Spring revolts.

But, for the world's major developed and emerging economies Monday's first order of business, after they are welcomed by their Mexican host President Felipe Calderon, will be to demand urgent action from Europe.

The eurozone leaders present -- Merkel, Hollande and Italian premier Mario Monti -- would prefer to solve their problems in-house at the European Union summit in Brussels at the end of this month.

But the imminent result of the Greek vote -- due on Sunday -- which could see a victory by forces opposed to the stark austerity imposed by an EU and IMF-led bail-out of Athens' debt, will concentrate minds in Los Cabos.

"It is extremely important that tomorrow's Greek elections lead to a result in which those who form the government say, 'Yes, we want to keep to our commitments'," Merkel told a regional meeting of her party on Saturday.

If Greece rejects its rescue package, under which voters facing poverty and joblessness were asked to accept harsh austerity measures, the country could default on its debts and find itself forced out of the single currency.

This in turn would send a signal to the bond markets that the European Union cannot guarantee all its members' finances, thus driving interest rates still higher for larger but still vulnerable economies such as Spain's.

Some of Berlin's European partners agree with those in Washington and Asia arguing Merkel should reduce the pressure on Greece by agreeing to more EU debt burden-sharing sovereign debts and looser austerity measures.

But she is expected to stand firm, despite China, India and the United States made it clear that there will be no let-up in their pressure.

"No one can escape unscathed when the ship capsizes among severe economic storms. Countries aboard the ship should extend a helping hand to each other," the official Chinese news agency Xinhua said in a commentary Saturday.

Indian Prime Minister Manmohan Singh, who has seen his own emerging giant's growth rate fall to its lowest in nine years, warned Europe's woes will further dampen global markets and adversely impact our own economic growth"

"It is our hope that European leaders will take resolute action," he said.

In Washington, Obama's administration made their own concerns clear.

Obama faces a tough presidential battle in November against Republican challenger Mitt Romney, and will be forced to defend his economic record even as the US economy struggles to create jobs.

US officials accept Europe is unlikely to unveil a comprehensive short and long-term plan to restructure its member states' debts at Los Cabos, but say privately that they now believe Germany and its partners are serious.

So, while the eurozone remains his main concern, Obama will also take the opportunity of the summit to meet his Chinese counterpart Hu Jintao and to pressure Putin on Russia's role in the Syrian conflict.

"Obviously, disagreements persist with regard to Syria, but it will be a good opportunity for the presidents to meet and work it through," said State Department spokeswoman Victoria Nuland, referring to the Mexico talks.

Western and Arab nations have been pressing Syria's President Bashar al-Assad to stand down and allow and allow a negotiated solution to the burgeoning civil war that has left more than 14,000 dead.

Russia has so far stood beside its traditional ally and stymied attempts to agree a unanimous UN Security Council stance on the crisis.

Again, no breakthrough is likely in Los Cabos. But the conflict in once more at a critical turning point, following the United Nations' decision to suspend its observer mission in the face of mounting attacks.

Assad is engaged in the brutal repression of a pro-democracy revolt by his own citizens and attacks by rebel fighters, and monitors say he continues to shell opposition strongholds despite a nominal UN-backed ceasefire.

Turkish Prime Minister Recep Tayyip Erdogan will be at the G20 pressing for the Security Council to take a "new measure" on Syria in the wake of the apparent failure of the UN-backed peace initiative.

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