With Syria escalation, Obama may win leverage on and off battlefield

US President's decision to deploy military advisors upended a year-old strategy hinged on supporting Syrian opposition fighters

US President Barack Obama's decision to send special operations forces to Syria is a calculated military escalation that could increase US leverage, both on and off the battlefield, say current and former US officials.

The policy shift coincides with an expanding clandestine CIA programme that channels weapons to opponents of Syrian President Bashar al-Assad and a new diplomatic push led by Secretary of State John Kerry to find a political solution to the conflict.

The addition of up to 50 US troops alone may not be enough to fundamentally change Syria's increasingly messy civil conflict. They are relatively tiny in number and will only be in an advisory and assistance role, leaving the United States still depending heavily on rebel allies who have not always proven reliable.

But it could help to blunt Middle East perceptions of US timidity in the wake of embarrassments for the Obama administration that have also fed domestic criticism of his foreign policy.

Those include the collapse of a half-billion-dollar Pentagon programme to train and equip Syrian fighters, and the unexpectedly rapid military intervention in Syria by Russian President Vladimir Putin in support of Assad. US government sources said Russia now has several thousand troops in the country backed by aircraft and armour.

The deployment of the military advisors upended a year-old strategy hinged on supporting Syrian opposition fighters battling Islamic State (ISIL) without putting American "boots on the ground".

"It's definitely meant to send a message that we're upping the game inside Syria, that we're absolutely serious about going after ISIL and that we're not going to be dissuaded by any efforts to prop up Assad," said an Obama administration official, speaking on condition of anonymity.

The strategy change also includes positioning more US jets in Turkey to expand American air strikes as Syrian Kurds, Arabs and other opposition fighters prepare to push toward the city of Raqqa, the Islamic State's defacto capital in Syria.

Fred Hof, a former State Department envoy on Syria, said the US deployment of a handful of forces alone was more of a Band-Aid than a game-changer. But it could open doors.

"By putting some 'skin in the game' on the ground in Syria, Washington may be able to make a credible pitch to regional powers to provide the ground combat components that can sweep ISIS from Syria," Hof said, using another common acronym for Islamic State.

Obama has vowed not to turn Syria into a proxy war with Russia, whose sudden ramping up of its military support for Assad caught Washington by surprise.

But the Central Intelligence Agency, in collaboration with Saudi Arabia and Qatar, recently broadened the number of groups to which it is clandestinely delivers weapons including TOW anti-tank missiles, one source familiar with the support operation said.