Moscow/Beirut: Russia and the United States have agreed to bury their differences over Syria and hold urgent international talks to find a settlement that can end the carnage of a civil war that is inflaming the entire Middle East.
Visiting Moscow after Israel bombed targets near Damascus and as President Barack Obama faces new calls to arm the rebels, US Secretary of State John Kerry said Russia had agreed to try to arrange a conference as early as this month involving both President Bashar al-Assad's government and his opponents.
East-West disagreement that has seen some of the frostiest exchanges between Washington and Moscow since the Cold War has deadlocked UN efforts to settle the Syrian conflict for two years, so any rapprochement could bring an international common front closer than it has been for many months.
Although the US has said Assad should not be part of a transitional government, Kerry said the decision on who takes part in it should be left to the Syrians.
But with Syria's factional and sectarian hatreds more entrenched than ever after 70,000 deaths, it is far from clear the warring parties are ready to negotiate. There was no immediate comment from the Syrian government, which has offered reforms but dismisses those fighting it as "terrorists".
The late hour of the announcement in Moscow - Kerry was kept waiting for three hours by President Vladimir Putin - also meant leaders of the Western-backed opposition umbrella group the Syrian National Coalition were not available for comment. Many on the body have insisted Assad's exit is a condition for talks.
Inside the country, where rebel groups are numerous and have disparate views, a military commander in the north, Abdeljabbar al-Oqaidi, told Reuters he would want to know details of the US-Russian plan before taking a view: "But," he added, "if the regime were present, I do not believe we would want to attend."
Alarmed at the prospect of the conflict spilling across an already volatile and economically important region, however, the major powers have, as Kerry told Putin late on Tuesday, "very significant common interests" in pushing for a settlement.
"The alternative," Kerry later told a joint news conference with Russian Foreign Minister Sergei Lavrov, "is that Syria heads closer to an abyss, if not over the abyss and into chaos.
"The alternative is that the humanitarian crisis will grow. The alternative is that there may be even a break-up of Syria."
At a conference in Geneva in June 2012, Washington and Moscow agreed on the need for a transitional government in Syria but left open the question of what would happen to Assad, whose departure Obama has called for but which Russia, accusing the West of meddling, says should be a matter for Syrians only.
Rejecting a characterisation of Moscow as the protector of Assad, to whose army it has been a major arms suppliers since the days of his father's rule, Lavrov insisted Russia was not concerned by the fate "certain" individuals.
"The task now is to convince the government and all the opposition groups ... to sit at the negotiating table," he said.
Kerry said the conference should be held "as soon as is practical - possibly and hopefully by the end of the month". Neither he nor Lavrov said where it might take place.
Kerry said there would be "a growing crescendo of nations who will want to push for a peaceful resolution, rather than the chaos that comes with the break up of a country".
Although the United States has said Assad should not be part of a transitional government in Syria, Kerry said the decision on who takes part in it should be left to the Syrians.
Lavrov said the aim would be "to persuade the government and the opposition together ... to fully implement the Geneva communique" on creating a transitional government.
Russia, backed by China which shares its mistrust of Western enthusiasm for toppling autocrats, has refused appeals to consider sanctions on Assad, vetoing three UN Security Council resolutions condemning his crackdown on opposition groups.
Recent developments have helped focus minds on the risks of wider war in the Middle East: intelligence reports that Assad's troops may have used chemical weapons had renewed calls for Obama to arm the rebels or even offer US forces; Islamist fighters pledging allegiance to al Qaeda has highlighted how some of the rebels are also hostile to the West; and Israeli air strikes in the past few days, said to target Iranian arms headed for Lebanon's Hezbollah, have underlined the risk of escalation.
Speaking before the announcement in Moscow, Assad was quoted by a sympathetic Lebanese television channel as saying he would defy Israel, the United States and Arab powers who oppose him: "The recent Israeli aggressions expose the extent of the complicity between the Israeli occupier, regional countries and the West in promoting the current events in Syria," he said.
"The Syrian people and their heroic army ... are capable of confronting this Israeli adventure, which represents one of the faces of terrorism that is targeting Syria every day."
While showing little desire to embroil US forces in Syria after winding down engagements in Iraq and Afghanistan, Obama has rejected criticism that he might back out of a commitment to act if Assad crossed a "red line" of using chemical weapons.
On Tuesday, he pointed to the killing of Osama bin Laden and of Libyan leader Muammar Gaddafi, brought down by US-backed rebels, as evidence that "we typically follow through on our commitments". It is still unclear if chemical weapons were used.
The chaos in Syria, where a fifth of the 25 million population has been driven from homes, was underlined by the latest incident of rebels taking UN peacekeepers hostage on the ceasefire line with the Israeli-occupied Golan Heights.
UN Secretary-General Ban Ki-moon strongly condemned the incident and called for the four Filipinos' immediate release. They were detained as they patrolled close to an area where 21 Filipino observers were held for three days in March 2013.
The Yarmouk Martyrs Brigade said they were taken in for their own safety during clashes in the area.
More widely, the violence in a religiously and ethnically diverse country at the heart of the Arab and Muslim world has inflamed a confrontation between Iran and its fellow Shi'ite allies like Hezbollah on the one hand and the Sunni Arab powers, including US ally Saudi Arabia, who back the Sunni rebels against Assad's Alawite minority, an offshoot of Shi'ite Islam.
Iran, at daggers drawn with Israel and the West over its nuclear programme, warned of unforeseeable consequences if Assad were toppled and said only a political settlement to Syria's civil war would avoid a regional conflagration.
"God forbid, if there is any vacuum in Syria, these negative consequences will affect all countries," Foreign Minister Ali Akbar Salehi said in Jordan. "No one knows what will happen."