Fears that the Islamic State is beginning to mass in its self-proclaimed Syrian capital of Raqqa and the possibility that the terror group may launch attacks from there are prompting the United States and its Western allies to put Raqqa in their crosshairs in the coming weeks.
U.S. and Western officials say they had always planned to sequester Raqqa, considered the terror group's most important stronghold. But they say the decision to move forward with the operation came just in the past few days, despite concerns that forces on the ground in Syria are not ready.
"There's an imperative to get isolation in place around Raqqa," the commander of Operation Inherent Resolve told Pentagon reporters Wednesday during a video briefing from Baghdad. "Our intelligence feeds tell us that there is significant external operations attacks planning going on."
FILE - In this file photo released June 23, 2015, provided by the Kurdish fighters of the People's Protection Units (YPG), which has been authenticated based on its contents and other AP reporting, Kurdish fighters of the YPG sit on their pickup in the town of Ein Eissa, north of Raqqa city, Syria.
"We know they're up to something," said Lt. Gen. Stephen Townsend, expressing a sense of urgency. "We're just not sure what they're up to and where and when."
The hope is that by isolating and increasing the pressure on Raqqa, the coalition can "try to head … off" whatever IS has planned.
Open road to Raqqa
While the intelligence surrounding Raqqa is new, the concerns are not.
U.S. and European intelligence officials have long worried that mounting losses in Iraq and Syria would force IS to increasingly shift its focus from maintaining its self-declared caliphate to terrorism.
FILE - In this file photo taken May 21, 2016, members of what the U.S. calls the Syrian Democratic Forces gather after a training session at a firing range in northern Syria.
U.S. officials have even repeatedly voiced concerns about threats from a so-called "terrorist diaspora" as IS fighters fled back to their homelands when the terror group's hold on territory crumbled.
Still, until recently most officials did not feel the need to focus so quickly on Raqqa.
"For a while we thought we would do Mosul and then Raqqa," a Western diplomatic official told VOA, speaking on condition of anonymity due to the sensitivity of the conversations.
That changed, the official said, as it became clear the various forces advancing on the Islamic State's Iraqi stronghold of Mosul were not going to be able to close off the city from the west.
The route from Mosul through the city of Tal Afar and then to Raqqa would be wide open.
"We're seeing a huge number of people fleeing Mosul to go to Raqqa," the official said. "Islamic State realizes that this is a route that is going to be key for them."
FILE - Iraq's elite counterterrorism forces gather outside Irbil, Iraq, Oct. 15, 2016.
Defense and intelligence sources describe the movement of people from Mosul to Raqqa as a steady trickle; not at all reminiscent of the massive convoys IS used to try to escape from their former Iraqi stronghold of Fallujah. And many of those fleeing Mosul for Raqqa are thought to be civilians.
Still, Western officials said the ranks of those fleeing included enough IS leaders and fighters that the coalition felt it had no choice but to increase the pressure on Raqqa now, even without all the needed forces in place.
"With Raqqa, what we have is mostly Kurdish forces," the Western diplomat told VOA, adding that both Turkey and Iraq have expressed concerns about Kurdish involvement in any operation to retake the Syrian city.
"We need an agreement between Turkey and the Kurdish militias," the diplomat said.
FILE - In this file image made from video posted online Oct. 16, 2016, by Qasioun News Agency, Turkish-backed Syrian opposition forces patrol in Dabiq, Syria.
U.S. military officials say talks with Turkey are ongoing but acknowledge that in the interim, a significant portion of the heavily Kurdish 30,000-strong Syrian Democratic Force (SDF) may not be available.
There are also plans to have the SDF's Arab contingents recruit and train fighters from the Raqqa area in the hopes of preparing them for a final assault on the IS-held city.
"It's absolutely possible that you could get the forces in place," said Daveed Gartenstein-Ross, a senior fellow at the Foundation for the Defense of Democracies.
"There's no love lost between the various forces that [are] working together to retake Mosul," he said, noting how Iraqi Army forces, Kurdish forces and Shia militias have so far managed to work together. "That provides some indication that, yes, they could get a coalition together to advance on Raqqa. They don't have to like each other to do that."
And Western officials are confident that despite the urgent threats emanating from IS leadership in Raqqa, they can buy enough time to cobble together an effective enough ground force to give the terror group a lasting defeat in what was once billed as a jewel of its self-declared caliphate.
"What we're doing right now is a pretty much continuous watch and [air]strikes," said the coalition's Townsend. "We're going to do those kinds of suppressive fires until we're ready to mount and approach an isolation of Raqqa."