* Russian and U.S. foreign ministers discuss peace moves
* International mediator to look for peace on Geneva model
* Clinton says working with Russia on political transition
* Anti-Assad rebels seeking international support
DUBLIN, Dec 6 (Reuters) - Russia and the United States will seek a "creative" solution to drag Syria back from the brink, the international mediator on Syria said on Thursday after meeting U.S. Secretary of State Hillary Clinton and Russian Foreign Minister Sergei Lavrov.
The comments by Lakhdar Brahimi, who called the unscheduled meeting on the sidelines of a Dublin conference, suggested a new coordination among the major powers could be emerging on Syria after months of sometimes bitter disagreement.
But statements from officials remained cautious.
A senior U.S. State Department official called the meeting "a constructive discussion focused on how to support a political transition in practical terms".
The next step would be a meeting "in the next few days" between Brahimi and senior officials from the United States and Russia "to discuss the specifics of taking this work forward", the official said.
Brahimi said he would seek peace based on the Geneva Declaration which calls for a transitional administration.
"We haven't taken any sensational decisions," he told reporters after the meeting at a gathering of the Organization for Security and Cooperation in Europe (OSCE). He called Syria's situation "very, very, very bad".
"We have agreed that we must continue to work together to see how we can find creative ways of bringing this problem under control and hopefully starting to solve it.
"We have also talked a little bit about how we can work out hopefully a process that will get Syria back from the brink. To put together a peace process that will be based on Geneva."
Clinton held a bilateral meeting with Lavrov and Brahimi met separately with Lavrov before the three sat down together. Clinton then had a short follow-on meeting with Brahimi.
She told a news conference before the talks that the United States had been trying hard to work with Russia to stop the bloodshed in Syria and start a political transition.
"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."
In Moscow, a senior Russian lawmaker and ally of Vladimir Putin described Syria's government on Thursday as being incapable of doing its job properly, in a sign Russia is trying to distance itself from President Bashar al-Assad.
That followed comments by Putin in Turkey on Monday that "new, fresh ideas" about how to end the crisis had emerged. The Kremlin said they would be discussed further by Russian and Turkish diplomats.
Assad's deputy foreign minister said meanwhile Western powers were whipping up fears of a fateful move to the use of chemical weapons in Syria's civil war as a "pretext for intervention".
RUSSIAN AND CHINESE OPPOSITION
The Dublin talks came ahead of a meeting of the Western-backed "Friends of Syria" group in Marrakech next Wednesday which is expected to boost support for anti-Assad forces, and could see the United States recognising a new rebel council as the legitimate representative of the Syrian people.
The rebels have made advances across Syria in recent weeks and fighting raged on Wednesday in an arc of suburbs on the eastern outskirts of Damascus.
Assad's family has ruled for 42 years and the president has vowed to fight to the death in a conflict that has killed an estimated 38,000 people and risks sucking in other countries.
Opposition sources said on Wednesday rebels, riven by deep divisions and rivalries, were trying to restructure their leadership across Syria in an effort to secure foreign funding for their armed revolt.
Brahimi has called for world powers to issue a U.N. Security Council resolution based on a June deal they reached in Geneva to set up a transitional government.
The Geneva Declaration, agreed when Kofi Annan was international mediator, called for a transitional administration but did not specify what role, if any, Assad would have.
The United States and its allies want Assad to step down. Russia has repeatedly said his fate cannot be decided outside Syria, but also appears to be trying to position itself for his potential exit.
Western countries proposed a new resolution at the U.N. Security Council in July aimed at putting direct pressure on Assad by threatening more sanctions unless his troops stopped using heavy weapons and withdrew troops from towns and cities.
Russia and China vetoed the resolution, saying it represented interference in Syria's internal affairs.
Annan stepped down in August, saying divisions in the Security Council made his plan unworkable.
The United States and its allies said the plan failed because of Assad's refusal to abide by its provisions and Russia and China's refusal to hold Assad accountable.
A group of bipartisan senators on Thursday said they stand ready to support President Barack Obama should he decide to use military force against Syria if it appears that Assad is preparing to use chemical weapons.
They also called on Russia, an ally of Assad, to become more active in trying to resolve the crisis.
Republican Senator John McCain, who has long advocated that the United States do more to help the Syrian rebels, told reporters he and three other senators - independent Joseph Lieberman, Democrat Chris Coons and Republican Lindsey Graham - were "deeply disturbed" by reports that Assad may have weaponised some of his stores of chemical and biological agents.
"If true, these reports may mean that the United States and our allies are facing the prospect of an imminent use of weapons of mass destruction in Syria, and this may be the last warning we get," McCain told reporters in Washington.
He criticized the Obama administration's policy of non-intervention since the rebellion began nearly two years ago.
"Time for talking about what to do may now be coming to a close and we may instead be left with an awful and very difficult decision," he said, describing the choice as whether to stay on the sidelines or take military action of some kind.
"We have now reached a point where there are weapons of mass destruction that may be used and also there is a significant question about the security of these weapons should Bashar Assad fall."
McCain said it was now up to the Russians "to do everything possible" to make sure Assad did not use chemical weapons.