(CBS News) More than 2,000 police officers from around the country were sworn in as deputy U.S. marshals Sunday in Washington. They'll be patrolling Monday alongside the D.C. police force, Secret Service, FBI, and other agencies, reports national security correspondent Bob Orr.
At Union Station, Transportation Security Administration VIPER security teams are checking trains and passengers, in a show of force designed to be a deterrent.
"If someone were to walk in and see a group of officers and turn around immediately and leave Union Station, that's a good indication to us that perhaps they have something to that they're trying to hide," Assistant Supervisory Air Marshal Jeffrey Buzzi said.
Not all security is so obvious. Two men with backpacks are undercover behavioral detection officers, working in tandem with uniformed patrols at rail stations and airports.
Along D.C.'s waterfront, Coast Guard fast boats are increasing surveillance runs. The cutter Cochito is a floating command center.
For 48 hours surrounding the inaugural time frame, the waters around Washington will be closed as more than 20 Coast Guard and police boats conduct patrols along 22 miles of shoreline.
At the edges of the restricted zone, the Coast Guard is watching for any "suspect" boaters -- "If they're in key specific areas or near critical infrastructure, if they're lingering there longer than normal, maybe if they're taking photographs from a certain angle," Coast Guard D.C. Commanding Officer Lt. Celina Ladyga told Orr.
A large swath of downtown Washington, from the Capitol to the White House, is cordoned off -- accessible only through metal detectors at checkpoints.
In all, more than 10,000 police officers, federal agents and National Guardsmen are on duty.
The Secret Service is coordinating the effort from its operations center, where analysts are monitoring surveillance cameras and real-time threat streams.
"Based on what we're hearing and seeing from our partners and what we're seeing internally, we feel that we are prepared," said Deborah Evans Smith, who runs the FBI's Washington field office. "No credible threat at this moment."
But nothing is being left to chance.
Miller also said a "render safe" team, comprised of agents from various agencies, will be on stand-by -- "sitting around playing cards, reading their BlackBerries" -- who have the capability to dismantle a nuclear device if one were found.
Miller said there are no credible threats on the radar, unlike Inauguration Day 2009, when there were two: "One was a major credible threat from al Qaeda that a group from Somalia was going to attack the inauguration," said Miller. "The other had to do with a guy coming down from Boston with a suicide vest, and both of those ended up washing out. But they certainly brought up the tension level. This time it's a little calmer."
Miller said the major concern is for the "lone wolf" threat, who may not have surfaced in the screens of intelligence analysts. "When you're looking at the international threat picture, what you're focusing on is networks, and there's sources and there's collection and there's intercepts. With the lone wolf, that's the guy who's going to end up in the crowd -- it's the John Hinckley, it's the Lee Harvey Oswald, it's the one who's probably spoken to no one, 'cause the conversation is going on in his mind. That's where you have a zero intelligence base and that's where the Secret Service really, really earns its money."
The president's security team -- the counter-sniper teams and counter-assault teams -- will also be put through their paces during the motorcade. "The dicey moment for the protectors, and the best moment for the president, is on the parade route when he pops out of the car," Miller said. "That thrills the crowd. I know the president enjoys it. But if you're one of the Secret Service agents, that's the time when the hairs all jump to attention on the back of your neck."