A Yemeni soldier looks at the graffiti of U.S. drone strike painted on a wall as a protest against the drone strikes, in Sanaa, Yemen, on Dec. 21, 2013. (Photo: Mohammed Mohammed/Xinhua)

Mattis Cites Iran As Reason US Will Assist Saudi Arabia In Bombing Campaign Of Yemen

Since the war began in 2015, some 10,000 people have been killed, including 4,000 civilians, and roughly 3 million Yemenis have been displaced, according to the United Nations.