Pretty much everyone is reporting it as "a shooter" and "gun shots", and MSNBC still has this on their main page:
Secret Service: Trump safe after being rushed off Pennsylvania stage after gunshot-like sounds
I saw statements from Biden, Obama, and Bush, which I have to say were all pretty fair and non-political and didn't mention gun control. Even Gabby Giffords only mentioned "political violence". I didn't see anything from Mr or Mrs Clinton.