World leaders were to fight for a consensus on Syria on the final day of the G8 summit Tuesday, after challenging Russian President Vladimir Putin to get on board or be left out in the cold.
The meeting of world leaders in Northern Ireland was also due to seek a deal on tax evasion but it was the divisions over the civil war in Syria that threatened to overshadow the second day of the gathering.
Presidents Barack Obama and Vladimir Putin struggled to hide their sharp differences on the conflict although they agreed they would push the fragile drive for a peace conference in Geneva.
In what appeared to be an attempt to face down Putin, British officials said the other seven G8 nations could go as far as issuing their own end-of-conference statement on Syria without Russia, which backs President Bashar al-Assad's regime.
Putin and Obama met for an hour of talks at the Lough Erne golf resort and in a grim-faced press conference afterwards said they had agreed to push all the parties in the conflict to attend a Geneva conference.
But the divisions between two nations that are now essentially arming different sides of the conflict were clear.
"Of course our opinions do not converge, but all of us have the intention to stop the violence in Syria and stop the growth in the number of victims," said Putin, who has shown contempt for plans by the White House to begin arming selected rebel groups in Syria.
He said he and Obama agreed that the vicious civil war must end "peacefully" and through peace talks.
"We agreed to push the parties to the negotiating table."
Obama simply acknowledged that they had "different perspectives" on Syria.
The US president also unveiled a new $300 million aid package for refugees inside and outside Syria.
Earlier, the British summit hosts raised the possibility of the other G8 nations issuing a statement about Syria without Russia, in what is bound to be seen as a provocative move by Putin.
"I think it is clarifying just what commitment Russia is prepared to make in a leading international forum," the official said.
British Prime Minister David Cameron was proposing a five-point plan at the dinner on Monday that he hoped would find common ground with Syria, the official said. It included calls for humanitarian access, and the shape that a transitional administration would take.
But a statement that chemical weapons are unacceptable was likely to be a sticking point as Russia has scoffed at US claims that the regime has used nerve gas.
Aside from Syria, Cameron is determined to find consensus on the issues of tax evasion and banking secrecy before the summit ends.
The OECD provided ammunition for a G8 offensive against tax evasion in a report outlining how to bring about automatic sharing of financial information, considered the key weapon in the fight against banking secrecy.
The report -- commissioned at the G8's request -- suggests that countries adopt broad, standardised legislation so that bilateral information-sharing agreements can be quickly and easily negotiated.
It warned that without solutions that cross continents, tax evaders will simply move to countries beyond the regulators' reach.
"Offshore tax evasion is a global issue requiring global solutions," noted the report, "otherwise the issue is simply relocated, rather than resolved."
It also urged countries to look at more than just bank accounts so that people do not simply shift their funds into other assets or vehicles such as trusts.
On Saturday, Cameron strengthened his hand by securing a commitment from Britain's overseas territories, including financial centres such as Bermuda and Jersey, to promote transparency and exchange of information between tax jurisdictions.
Last year the United States and five European countries decided to move in the same direction by drafting a model agreement based on a 2010 US law.
It obliges all banks to automatically provide US authorities with all information they hold concerning all assets owned by US taxpayers, instead of upon request as was previously the practice.