"There are those saying we should not close down the streets around these facilities. I think we need to get used to that concept," he continued. "Forty-two thousand people is an attractive target for people who want to hurt us. And a ballpark that's about 6 feet, at one point, from the street is as big a target as any we can imagine. So I think we need more resources, and I think we need to redouble our thoughts on how to keep ourselves safe."