WASHINGTON (MCT) U.S. aircraft and "partner nation forces" struck Islamic State targets inside Syria early Tuesday in the first strikes in that country since President Barack Obama said he would expand the U.S. campaign against the Islamist militant group Sept. 10.

Pentagon spokesman Navy Rear Adm. John Kirby provided few details of the strikes, saying the operations are "ongoing."

Kirby's statement said the decision to strike inside Syria had been made Monday, Washington time, by the U.S. Central Command commander "under authorization granted him by the commander in chief." It was unclear when Obama had issued the authorization or whether the president had approved the specific targets of the attacks.

"I can confirm that U.S. military and partner nation forces are undertaking military action against ISIL terrorists in Syria using a mix of fighter, bomber and Tomahawk Land Attack Missiles," Kirby's statement said. "Given that these operations are ongoing, we are not in a position to provide additional details at this time. The decision to conduct these strikes was made earlier today by the U.S. Central Command commander under authorization granted him by the commander in chief. We will provide more details later as operationally appropriate."

There are a variety of potential targets inside Syria for such a strike, including the Islamic State's headquarters at Raqqa.