Bloomberg reports here in "Warship Ruse and New Stealth Missiles: How the U.S. and Allies Attacked Syria":
While both vessels carry as many as 90 Tomahawk missiles -- the main weapon used in the Friday evening strike on Syria -- neither ship in the end fired a shot. Instead, according to a person familiar with White House war planning, they were part of a plan to distract Russia and its Syrian ally from an assault Assad’s government could do little to defend itself against.