DUBLIN — Diplomatic efforts to end Syria's civil war moved forward Thursday with Secretary of State Hillary Rodham Clinton joining Russia's foreign minister and the U.N. peace envoy to the Arab country for extraordinary three-way talks that suggested Washington and Moscow finally might unite behind a strategy as the Assad regime weakens.
In Washington, Defense Secretary Leon E. Panetta said intelligence reports raise fears that an increasingly desperate Syrian President Bashar Assad is considering using his chemical weapons arsenal — which the U.S. and Russia agree is unacceptable. It was unclear whether Mr. Assad might target rebels within Syria or bordering countries, but growing concern over such a scenario clearly was adding urgency to discussions an ocean away in Ireland's capital.
On the sidelines of a human rights conference, Mrs. Clinton gathered with Russian Foreign Minister Sergey Lavrov and U.N. envoy Lakhdar Brahimi to look for a strategy the international community could rally around to end Syria's 21-month civil war. The former Cold War foes have fought bitterly over how to address the conflict, but Mrs. Clinton stressed before the meeting that they shared a common goal.
"We have been trying hard to work with Russia to try to stop the bloodshed in Syria and start a political transition for a post-Assad Syrian future," Mrs. Clinton told reporters in Dublin.
"Events on the ground in Syria are accelerating, and we see that in many different ways," she said. "The pressure against the regime in and around Damascus seems to be increasing. We've made it very clear what our position is with respect to chemical weapons, and I think we will discuss that and many other aspects of what is needed to end the violence."
Earlier Thursday, Mrs. Clinton and Mr. Lavrov met separately for about 25 minutes. They agreed to hear Mr. Brahimi out on a path forward, a senior U.S. official said. The two also discussed issues ranging from Egypt to North Korea, as well as new congressional action aimed at Russian officials accused of complicity in the death of lawyer Sergei Magnitsky.
Washington and Moscow have more often publicly chastised each other than cooperated on an international strategy for Syria. The U.S. has criticized Russia for shielding its Arab ally. The Russians have accused the U.S. of meddling by demanding Mr. Assad's downfall and ultimately seeking an armed intervention such as the one last year against the late Libyan strongman Moammar Gadhafi.
But the gathering of the three key international figures suggests possible compromise in the offing. At a minimum, it confirms what officials describe as an easing of some of the acrimony that has raged between Moscow and Washington over the future of Syria, an ethnically diverse nation whose stability is critical, given its geographic position in between powder kegs Iraq, Lebanon and Israel.
Mr. Panetta said Thursday that the U.S. fears Syria is thinking of using its chemical weapons.
"The intelligence that we have raises serious concern that this is being considered," he told reporters. Other administration officials in recent days have spoken about Syrians preparing weapon components of sarin gas. The new activity, coupled with fears that rebel advances are making Mr. Assad more desperate, have led to the fear that he is deploying the weapons.
On Thursday, Syrian Deputy Foreign Minister Faisal Mekdad accused the United States and Europe of using the issue of chemical weapons to justify a future military intervention against Syria. He warned that any such intervention would be "catastrophic."
It's unclear what new approach Mr. Brahimi may outline. One possibility would involve resuscitating, with U.S. and Russian support, the political transition strategy both countries agreed on in Geneva in June.
That plan demanded several steps by the Assad regime to de-escalate tensions and end the violence that activists say has killed more than 40,000 people since March 2011. It would then have required Syria's opposition and the regime to put forward candidates for a transitional government, with each side having the right to veto nominees proposed by the other.
If employed, the strategy surely would mean the end of more than four decades of an Assad family member at Syria's helm. The opposition has demanded Mr. Assad's departure and has rejected any talk of his staying in power. Yet it also would grant regime representatives the opportunity to block Sunni extremists and others in the opposition that they reject.
The transition plan never got off the ground this summer, partly because no pressure was applied to see it succeed by a deeply divided international community. Mr. Brahimi's predecessor, former U.N. Secretary-General Kofi Annan, who drafted the plan, then resigned his post in frustration.
The United States blamed the collapse on Russia for vetoing a third resolution at the U.N. Security Council that would have applied world sanctions against Mr. Assad's government for failing to live by the deal's provisions.
Russia insisted that the Americans unfairly sought Mr. Assad's departure as a precondition and worried about opening the door to military action, even as Washington offered to include language in any U.N. resolution that would have expressly forbade outside armed intervention.
Should a plan similar to that one be proposed, the Obama administration is likely to insist anew that it be internationally enforceable — a step Moscow may still be reluctant to commit to.
In any case, the U.S. insists the tide of the war is turning definitively against Mr. Assad.