Police are searching for a gunman who shot dead two students and injured nine others at Brown University in Providence, Rhode Island.
Police say the attacker was a man dressed all in black who fled on foot, and a shelter-in-place warning is in effect for the area surrounding the prestigious university.
The attack on the campus brings the number of mass shootings in the US to 389 for this year, according to the independent analysis website Gun Violence Archive.
It defines mass shootings as having four or more victims killed or injured, not including the attacker.
Here's what we know:
