deploying more officers around the city. >> you'll see them in the airports, you'll see them in the tunnels. it's not because there's any evidence of any ongoing threat or any additional threat, it is just out of vigilance and out of -- out of caution. >> reporter: security stepped up tonight on the night millions of parents and their children are out on the streets trick or treating. the scene of that attack, just blocks away from greenwich village, where tens of thousands of people are expected at the annual halloween parade. that parade is going forward tonight with heavy police presence. >> more police officers, heavy weapons teams, blocker vehicles on the street leading to the route, as well as more sand trucks. there's also heavy weapons teams being deployed throughout the city at key, iconic locations. >> reporter: the nypd has been long prepared for the possibility of vehicle attacks. beefing up security around public events and high profile