From National Review:

The Associated Press Stylebook was amended this week to discourage the use of the word “riot” to describe violent protests, instead expanding the definition of “protest” to include violent demonstrations.
“Use care in deciding which term best applies: A riot is a wild or violent disturbance of the peace involving a group of people. The term riot suggests uncontrolled chaos and pandemonium,” said the AP Stylebook, which sets style guidelines followed by many mainstream media publications.