Here a statement from a U.S. Official
Update: The number of missiles is now between 50 and 60.
April 6, 2017 (WASHINGTON) The United States has launched 50 Tomahawk missiles from two US Navy vessels in the eastern Mediterranean. This is following a chemical attack in the northern province of Idlib Province. According to the New York Times, the presence of Sarin was confirmed by Turkish officials.
Over 100 people were killed or injured.
The targetted facility is a Syrian air force base in the western part of the country, and it is not yet clear if this is the only strike or just degradation of facilities.
There is no word on casualties.