The U.S. military is now committed to begin a first-of-its-kind joint military operation with Russia, mounting airstrikes against the Islamic State group in Syria.

Yet its not clear what the military advantage will be for the U.S. ground-level operations against the Islamic State.

"With respect to what the Russians might bring to this fight, I'm not going to speculate about that right now," Lt. Gen. Jeffrey Harrigian, the head of U.S. Air Forces Central Command, told reporters Tuesday.

"That would probably be better asked at the diplomatic level," he said in a press briefing.

Top U.S. diplomats acknowledge that the military cooperation does not really have any strictly military goals but is instead part of a broader political strategy to halt the Syrian civil war.

The joint operations -- long sought by the Russians -- could begin as early as next week if, and only if, Russia and the Syrian regime both adhere to the cease-fire agreement that the U.S. and Russians announced Saturday.

The U.S. and Russians would set up a "joint integration center" for sharing intelligence and coordinating air strikes on Islamic State militants and the al Qaeda-linked group known as al-Nusrah, which both countries consider enemies, Harrigian said.

The joint operations would be highly unusual, considering the U.S. broke off official military-to-military relations with the Russians in 2014 after the Russians invaded the Crimea peninsula. And in Europe, U.S. military leaders say their approach to Russia has shifted to a Cold War-era strategy of "deterrence."

Many details of the military cooperation remain unresolved. Where will this joint integration center be? Will the U.S. and Russia operate in the same airspace? How will the U.S. share information without disclosing its own classified tactics, techniques and procedures? And how will the U.S. ensure that that the Russian air force does not use "dumb bombs" and cause massive civilian casualties?

"That will be something that we'll have to work out. … We've got work to do to understand what that plan is going to look like," Harrigian said.

For now, military leaders remain deeply skeptical. "I’m not going to say I trust them," Harrigian said.

Yet the deal for military cooperation with Russia is part of a broader American political and diplomatic effort to end the 5-year-old Syrian civil war that has fueled extremism, provided safe havens for the Islamic State group and sent waves of refugees into Europe.

"The U.S.-Russia plan is designed to advance the process of trying to reduce the violence so that we can get people to a table ... and begin to negotiate a political transition and the restoration of a peaceful and united Syria," Secretary of State John Kerry said Monday.

A key component of the deal will prohibit the Syrian regime from flying combat missions over some areas controlled by rebel opposition forces, including some groups backed by the United States. And ultimately, the U.S. hopes Russia will lean on its ally, Syrian President Bashar Assad, to reach a negotiated settlement.

"For the Russians it would … give them a measure of coordination with the U.S. military that they don't have right now and that they have expressed an interest in," said John Kirby, a State Department spokesman.

"For us, it gives us a real shot at keeping Assad from barrel bombing and gassing his own people as well as the opposition; and more critically, if a cessation of hostilities can be maintained and reduced violence can be established and sustained, and humanitarian access, get the opposition back to the table with the regime in Geneva under the [United Nations], get a political process started. That's the real goal here," Kirby said.

U.S. Secretary of State John Kerry, left, and Russian Foreign Minister Sergei Lavrov conclude a joint press conference following their meeting to discuss the crisis in Syria, in Geneva, Switzerland, on Friday

Photo Credit: Kevin Lamarque/Pool Photo via AP

The Air Force general said he understands that the military operation is one piece of a larger effort.

"The diplomatic-to-military piece is always something that we've got to stay engaged with and something that we understand is all part of the process as our diplomatic leaders continue to work what are very challenging problems, quite frankly, for the world," Harrigian said.

He said his main goal is to make sure the fight against the Islamic State continues.

"From my perspective, my job will be to, number one, ensure that as this moves forward, we're comfortable that the guidance that we get is operationalized into a process that allows us to continue the momentum that we have against ISIL; build on the coalition that we have put together to allow us to continue to pressure Daesh," Harrigian said.