What’s the damage of the Deflect Missile attack?

@JeremyECrawford When a monk using "Deflect Missile" catches and throws a projectile, whats the damage of the attack? #DnD

— Nacho Girbés Llácer (@NGirbes) October 21, 2015

A missile counts as a monk weapon if thrown via Deflect Missiles; it deals its damage or Martial Arts damage. #DnD https://t.co/hDcaGV33xM

— Jeremy Crawford (@JeremyECrawford) October 24, 2015