ENNISKILLEN, Northern Ireland – President Obama, Russian President Vladimir Putin and other G-8 leaders attempted to speak with one voice Tuesday on seeking a negotiated Syrian peace settlement — yet couldn't publicly agree on whether this means that President Bashar Assad must go.

Their declaration at the end of the two-day Group of Eight summit sought to narrow the diplomatic chasm between Assad's key backer, Russia, and Western leaders on starting peace talks in Geneva to end a two-year civil war that has claimed an estimated 93,000 lives.

G-8 leaders also published sweeping goals for tightening the tax rules on globe-trotting corporations that long have exploited loopholes to shift profits into foreign shelters that charge little or no tax.

But that initiative, aimed at forcing the Googles and Apples of the world to pay higher taxes, contained only aspirations, not binding commitments.

The declaration on Syria said the country needs a new coalition government with "a top leadership that inspires public confidence," a definition that to British, French or American eyes would rule out Assad. It made no reference to sending U.S., British or French weapons to rebels, an option being kept open by the three G-8 members.

Russia refused to back any declaration that made Assad's ouster an explicit goal, arguing that it would be impossible to start peace talks with a predetermined outcome.

Reflecting the profound divisions that remain, the British host, Prime Minister David Cameron, said it was "unthinkable that President Assad can play any part in the future government of his country. He has blood on his hands. He has used chemical weapons."

Putin — speaking at the same time as Cameron at a different location in a gesture that some diplomats construed as rude — rejected Cameron's views as unproven. And referring to last month's butchery of an off-duty British soldier, Putin warned Cameron that the weapons sent to Syria might end up being used to kill people in Europe.

Reflecting growing unease at the behavior of Muslim extremists in the ranks of Syria's splintered opposition forces, the G-8 declaration said participants in peace talks must agree to expel al-Qaida-linked fighters from the country.

The declaration condemned human rights abuses committed by government forces and rebels alike, and called on both sides to permit access by U.N.-led chemical weapons experts trying to investigate the contentious claims of chemical weapons use.

In its only concrete commitment, the plan pledges a further $1.5 billion in aid for Syrians driven from their homes by the conflict: 4.2 million within Syria and 1.6 million more taking refuge in neighboring countries. The G-8 noted that the new funds would cover only part of the U.N. appeal for $5.2 billion in Syria-directed aid.

Rebels, who have seen tactical reversals in recent weeks vs. Assad's Russian-supplied army, expressed disappointment with the G-8 verdict.

"We expected more," said Loay AlMikdad, a spokesman for the Free Syrian Army, speaking by telephone from Turkey. "We expected a more solid statement, a more decisive one."

He said the Free Syrian Army hopes the statement's weakness would be counterbalanced by strong Western intervention on the ground to send weapons. This, he said, would help deter al-Qaida-influenced movements from taking root in rebel-held areas.

But a White House official, speaking to reporters as Obama flew to Berlin, said the U.S. administration was pleased with the outcome and had been braced for less agreement. "This in no way minimizes the difficulties ahead," deputy national security adviser Ben Rhodes said. "But given the various ways the G-8 could have gone, we believe that on the key issues of political transition, humanitarian support and chemical weapons investigation, it's very helpful to have this type of signal sent by these eight countries."

Earlier, G-8 leaders announced new goals to combat tax avoidance by multinational companies. In a joint statement, they said tax authorities should share information "to fight the scourge of tax evasion" and make it harder for companies to "shift their profits across borders to avoid taxes."

A key principle in the plan would require multinationals to declare how much tax they pay in each country.