After months of battlefield stalemate, a flurry of reports suggest a new clandestine effort is under way to open a "southern front" against the Assad regime.
Central to the plan is a renewed push to provide Syria's badly divided and often ineffectual moderate, secular rebel groups with additional funds, upgraded weapons and intelligence support.
The initiative, as reported in the region, is set against a backdrop of secret talks in the United States last month between Susan Rice, Barack Obama's national security adviser, and Prince Mohammed bin Nayef, the Saudi interior minister in charge of covert action programmes in Syria.
According to the usually well-informed columnist David Ignatius of The Washington Post, spy chiefs from Jordan, Turkey, Qatar and other regional countries also attended the discussions, focused on making a "stronger effort" to help the rebels.
This meeting has been linked in turn to last month's launch by the Free Syrian Army (FSA) of what they termed a spring offensive in the south of the nation. The offensive began days after they received new US weapons funding that may eventually total more than US$30 million, rebel commanders said.
After holding back for months owing to fears that new arms might fall into the hands of al-Qaeda affiliates, officials said the US Congress had given approval in January for more cash for light weapons intended for the secular opposition in the south.
The new US funding supposedly augments a fresh push by Arabian Gulf states to finance rebel operations in the southern region of Syria, which are ultimately aimed at Damascus.
According to various reports, mostly based on rebel statements or official or semi-official information leaks, the aim of the offensive is to push back government forces in the Daraa, Quneitra and As-Suwayda regions in southwest Syria, so opening the road to Damascus.
This emphasis on military action along the southern front follows well-documented concern that the predominance in northern and eastern Syria of jihadis belonging to the al-Nusra Front, which is linked to al-Qaeda, and rival groups such as the Islamic State in Iraq and the Levant has become both destructive and counterproductive.
Detailed media reports in regional publications claim the operational plans, supply routes and tactics for the new push are being overseen by a secret international operations command centre in Amman, Jordan, staffed by military officials from 14 countries, including the US, Britain, Israel and Arab states opposed to Bashar al-Assad.
"Rebel fighters and opposition members say the command centre, based in an intelligence headquarters building in Amman, channels vehicles, sniper rifles, mortars, heavy machine guns, small arms and ammunition to Free Syrian Army units," the Abu Dhabi-based National newspaper reported.
Jordan denies the existence of the centre and of reportedly US CIA-run rebel training facilities in northern Jordan.
"I have never heard of this," Zuhdi Janbek, director of Jordan's special branch, said.
None of the Western or Arab states that have intelligence and military staff working at the centre, the Military Operations Command, had publicly acknowledged it, but the centre's existence had become an open secret, the National claimed.
Whatever the accuracy of such reports, there is little doubt that Jordan's officially neutral stance over the Syrian war is threatened by the increasing importance of the southern front as the conflict enters its fourth year.
Despite Amman's denials, it is known to have close links with Western intelligence.
It is also widely believed that its territory is being used by the moderate opposition to assist and direct anti-Assad operations.