The United States and Turkey have agreed "in principle" to begin providing air support to Syrian rebels being trained to fight against Islamic State group militants, according to Turkey's foreign minister.

The agreement signals what could be an expansion of U.S. involvement in the conflict, and has the potential to appease Republicans who say President Obama's current strategy isn't working. U.S. officials didn't immediately comment on the supposed agreement, according to Reuters.

Washington has long been providing training and weapons to "moderate" Syrian rebels fighting against both the Islamic State group and Syrian President Bashar al-Assad, and has more recently been conducting airstrikes against the extremist group in Syria. But U.S. officials have been hesitant to commit to enforcing a "safe zone" for Syrian rebels, as it could be interpreted by the Syrian government as a declaration of war, since many of those rebels are also fighting to overthrow the Syrian regime, according to Reuters.

Turkish Foreign Minister Mevlut Cavusoglu told the Daily Sabah on Monday that the air support would protect Syrian rebels who have been trained by a U.S. program in Turkish territory. Some 15,000 of those rebels would then be sent back into Syria to fight the Islamic State group.

"They have to be supported via air. If you do not protect them or provide air support, what is the point?" Cavusoglu told the Daily Sabah. "There is a principle agreement on providing air support. How it is going to be provided is in the responsibility of the army."

The U.S.-led training program in Turkey has been mired in delays due to fundamental disagreements as to the purpose of the mission.

Turkey insists that any support program must also include a comprehensive plan to directly fight against Assad's regime, but Washington reportedly favors taking a more indirect approach.

Cavusoglu acknowledged that defeating the Islamic State group is the current priority, but insisted that the Assad "regime must also be stopped."