The U.S. military will accelerate its plan to cut off the Syrian capital of the self-proclaimed Islamic State, in part, because it has seen evidence the terror group is planning attacks against the West, the top general in charge of the U.S. war effort said Wednesday.

And just what kind of “external threat” ISIS is plotting is unclear, U.S. Army Lt. Gen. Stephen Townsend said at a Pentagon news briefing, and U.S. officials don’t know when and where ISIS is planning to attack next. “We know they are plotting something,” he said.

The “sense of urgency” is so great that the U.S. appears willing to anger its top regional ally, Turkey, by including local Kurdish forces, despite vehement Turkish opposition.

Townsend’s announcement that the Kurdish YPG would be part of the Raqqa campaign were the boldest public statements yet on how much the U.S. is willing to back one of the only local ground forces that could confront ISIS—even over objections from a key NATO ally.

“The only force that is capable on any near term timeline are the Syrian Democratic Forces, of which the YPG are a significant portion,” Townsend said. “We’ll move soon to isolate Raqqa with the forces that are ready to go.”

Townsend outlined the challenges of ending ISIS’s grip on Raqqa, given Turkey’s objections, the demands of the local Kurdish forces, the ongoing civil war and the limited U.S. engagement on the ground there. For example, he called reaching a deal with Turkey “tough” but at the same time said: “We’re going to go with who’s willing to go soon.”

Essentially, Townsend said the U.S. is willing to move on isolating Raqqa even as it has yet to settle the geopolitical implications of the Raqqa operation – on U.S.-Turkish relations and on Turkish-Kurdish relations. Moreover, it is not clear what forces would eventually enter the city. Townsend said, in addition to the Kurdish dominated Syrian Democratic Forces, which includes the YPG, there are plans to train additional local forces, presumably Sunni Arabs, to eventually enter Raqqa at a later date.

It is not clear whether Townsend was communicating to the international community, or the administration, and if so, what kind of message he was sending.

After all, there is nothing to indicate that the YPG have said they would be willing to isolate or enter the Arab-dominated city of Raqqa. If they did approach Raqqa, it likely would be from the Syrian cities of Kobani and Manbij. Meanwhile, the Turkish foreign minister has said cooperating with the YPG in its advance on Raqqa would endanger the future of Syria.

Townsend said the U.S. currently is negotiating with Turkey over what role the Kurds and Turkey could have in the eventual liberation of Raqqa.

“What happens after [the isolation of Raqqa] is still to be determined,” Townsend said.

How soon the isolation campaign, or prepping the battlefield for ground forces to enter, remains unclear. On Tuesday, Carter said the Raqqa offensive would begin “within weeks.” Townsend refused to be that specific, noting he did not want to tip off the enemy. He did however, predict that Raqqa will take longer to fall than Mosul. Two weeks ago, Iraqi forces, Kurdish peshmerga, with U.S. airstrikes and advisers on the ground, began the fight to reclaim that city from ISIS, which has controlled Iraq second-largest city since June 2014.

Still others note that Raqqa is far more challenging a fight than Mosul. And with so many outstanding questions, it is better to wait and sort out the kinks than to rush in.

For Turkey, the use of those Kurdish forces, even just to isolate Raqqa, would embolden what it considers a terror group. The U.S., however, considers the Kurdish forces, including YPG, to be the best fighting local ground forces, and a keystone to the collapse of ISIS.

The decision to start isolating Raqqa even as it key questions remain unclear, was the latest overt signal yet that, for the U.S., killing ISIS is more important than resolving the ongoing civil war there.

“The priority remains fighting ISIS over resolving the Syrian civil war. And that is going to make ending the war harder,” said Jenny Cafarella, a Syria expert at the Washington D.C.-based Institute for the Study of War. “We just gave Turkey more power. It is now Turkey that represents the best interests of the Syrian opposition because the U.S. is unwilling to slow down the anti-ISIS fight in order to involve the opposition in that fight.”