A commander with the rebel Free Syrian Army (FSA) has offered a 25-million-dollar bounty for anyone who captures Syrian President Bashar Assad "alive or dead," reported the Turkish news agency Anatolia on Tuesday.

The announcement by an unnamed commander with the FSA said the money for the bounty had been set up with donations from anti-Assad business people.

The reported bounty offer came as Western officials said Tuesday there was little doubt a growing number of foreign jihadi fighters are entering the fray in Syria, although it is far from clear whether any have direct links to Al Qaeda. But it is just one worry amongst many.

"This is not a situation where the US can do much to shape what happens," says Ms Mona Yacoubian, a former State Department official and now fellow and Syria expert at the Stimson Centre. "There has always been a lot of caution within the Obama Administration on Syria and if anything things are getting more complicated."

Working with Libya's initially notoriously disorganized rebels, officials complained, was hard enough; but the opposition to Assad seems even more diffuse.

That makes policy-making much more complicated and supplying weapons, or even choosing who to talk to, more of a gamble.

"We badly need to identify some political and military leaders who can make clear that they seek a political settlement to bring all fighting to an end," said one Western official on condition of anonymity. "Without that the bloodletting reinforces the worst aspects of sectarianism and makes a soft landing ever less likely."

Western states have been on a concerted offensive to push opposition figures towards greater unity, facilitating meetings that range from foreign-based conferences to Internet chats and small border gatherings.

But, beyond pushing in humanitarian aid they fear there is a limited amount they can do to change the situation on the ground.

"It's a very difficult situation, and the lack of coherence of the opposition is probably the biggest single challenge," says Ms Melissa Dalton, a senior Pentagon adviser on Syria and the Middle East currently on sabbatical as a visiting fellow at the Centre for New American Security.

"Given everything that is at stake, the United States clearly cannot do nothing. But there are no good scenarios arising from this conflict, and so the most important strategy for the United States to pursue is mitigating the risks to its interests."

That meant to prioritize tracking Syria's chemical weapons, ensuring militant groups inspired by Al Qaida were unable to set up safe havens and preventing weapons from falling into the wrong hands, she said. It also meant avoiding doing anything to make matters worse.