Prime Minister David Cameron wants Russian President Vladimir Putin to sign up to what he hopes will become an international peace plan to end the conflict in Syria but may have to press ahead without him, British officials said on Monday.
Cameron was planning to gauge Putin's views over a dinner at the G8 summit in Northern Ireland that officials described as "a potential clarifying moment" where he hoped to find consensus among global leaders on five specific issues.
"It's a clarifying moment to see what kind of commitments the Russians are willing to make in a leading world forum," said one official before the dinner.
But if consensus couldn't be reached it was possible a final statement at the end of the two-day summit might be released without Russia's input and in the name of the G7 rather than the G8, officials indicated.
Cameron hopes the statement will pave the way for a Syrian peace conference in Geneva that will agree the details of how a transition government can assume the powers of President Bashar al-Assad's administration.
"There has to be a statement that we can all sign up to or one that some can't," the same official said.
The West had repeatedly clashed with Russia over how best to end the conflict in Syria with Moscow thwarting attempts to condemn Assad in the United Nations while selling weapons to his army.
U.S. President Barack Obama sparred with Russia's Vladimir Putin over how to end the fighting on Monday during an icy encounter at the summit where divisions over the conflict eclipsed the rest of the agenda.
Speaking after talks with Obama, Putin said Moscow and Washington had differing views over Syria but agreed that the bloodshed must stop and that the warring parties should be brought to the negotiating table.
The United States said last week it would step up military assistance to the Syrian rebels fighting to overthrow Assad, but Britain and France have stopped short of matching that commitment, and the focus now is on trying to get a peace conference underway.
British officials said Cameron, whose country is chairing the G8, is hoping to forge a G8 consensus on five specific issues regarding Syria: on humanitarian aid and access, on how to tackle Islamist extremists, on condemning the use of chemical weapons, on formulating a stabilisation strategy, and on managing a transition to a new government.
But he was not planning to broach the divisive subject of arming the opposition since there was no consensus on the issue, officials said.
The dinner was held in a lodge on the shore of Lough Erne where the leaders discussed Syria over a dinner of crab, fillet of beef, and whisky-laced custard.
On chemical weapons, officials said they expected a discussion between Russia and the others about evidence of their use, something Moscow has so far said it sceptical about.
On the activities of radical Islamists, officials said there was growing consensus between Russia and the West about the threats they posed.
"What we and the Americans are increasingly concerned about is instability, the space it is providing for terrorists. And the knock-on effect for groups like Hezbollah," the official said.
"The Russians also have ... concerns about the roots (of terrorism) up to parts of Russia and the impact it has on them."