A SENIOR OBAMA administration official tells Fox News that the US would retaliate against Syria's air defenses if Bashar al-Assad's forces attack American planes carrying out airstrikes against ISIS on Syrian territory. US launches first offensive airstrikes against ISIS in IraqAyatollah, US spar over Iran role in fighting ISIS as Kerry seeks coalitionWhite House claims that Arab nations offer to join airstrikes against ISIS militantsOPINION: The SS Barack Obama is sinking fast, could be too late to saveUS programs will counter extremists | VIDEO: Kerry, coalition hold talks VIDEO: US rallies global support against ISIS | VIDEO: Can ISIS be destroyed without ground troops?