As U.S. forces gear up for airstrikes in Syria, the first demonstration of President Barak Obama's more aggressive military campaign against the Islamic State group is likely to unfold as early as next week — in Iraq.

Planes and drones will be conducting intelligence-gathering flights over Syria for future airstrikes. But meanwhile, more targets are expected to come under attack over a wider area of Iraq. Those could include strikes against Islamic State leaders, officials said Friday.

The Pentagon's press secretary, Navy Rear Adm. John Kirby, said that with Obama's new authorization, the air campaign in Iraq will soon switch from a mainly defensive approach to an offensive mode.

Kirby also said the Pentagon foresees training more than 5,000 Syrian rebels at bases in Saudi Arabia over the coming year.