Could be, but I think it will be another press conference. That's the way they've been communicating. I think he was just giving the media a headsup on that as well as letting the terrorists know that the government is considering how to respond.
BTW, I want to point out that this guy didn't say "your children aren't safe at school". He said they're not safe anywhere, anytime. Hopefully, he was just talking about gunshots. But this implies we may see some home invasions pretty soon or even machine gun attacks in public places.
I would not be surprised to see more schoolyard attacks, as well as attacks on people around their homes outside. Or in parks. So far, the guy has stuck primarily with public venues like stores and gas stations - but I think that if he isn't caught soon, he will start taking other approaches, particularly if stirred up by public speculation about what he can/can't do and what he will/won't do.