More than two dozen federal agencies are joining forces with police to bring an unprecedented level of security to the annual Rose Parade in Pasadena, California, in the aftermath of the deadly mass shooting this month in nearby San Bernardino.

Extraordinary security measures planned for the New Year's Day event include more than a dozen armed tactical "rapid-response" teams to be posted along the parade route, along with dozens of surveillance cameras, bomb-sniffing dogs and radiation-detection devices, law enforcement officials said.

Some 700,000 spectators are expected to turn out in Old Town Pasadena, north of the Los Angeles, for the 127th Tournament of Roses Parade, a 5 1/2-mile procession of flower-adorned floats, marching bands and equestrian teams. Millions more will watch the two-hour event on live television.

The 102nd Rose Bowl college football classic after the parade also will be televised live, with about 92,000 fans expected to pack the Rose Bowl stadium for the game.

Both the parade and game are designated for the first time among a handful of major U.S. public events - including the NFL's Super Bowl - as top-level concerns by the U.S. Department of Homeland Security, said Mark Selby, deputy special agent in charge of the agency's investigative bureau in Los Angeles.

Although no specific credible threat has been made against either Pasadena event, the precautions being taken mark the largest security operation in the 100-year-plus history of the Rose Parade and Rose Bowl, Selby said on Monday.

The level-1 security rating was made last year, though Selby acknowledged that even more personnel were assigned after 14 people were shot dead Dec. 2 at a holiday gathering by an Islamic extremist couple in San Bernardino, about 55 miles east of Pasadena.

"The San Bernardino event sort of upped the ante," he told Reuters.

Pasadena city spokesman William Boyer said the public will notice a heightened police presence, with some officers carrying rifles, "and there will be a lot of things they won't see that will be going on."

Police Chief Phillip Sanchez said less-visible precautions would include two dozen undercover officers patrolling the parade route, which also will be monitored by several dozen surveillance cameras. Additional surveillance is to be provided by U.S. Customs and Border Protection aircraft flying over the event, Selby said.

Automatic license-plate reading devices also will be set up to collect data on suspicious vehicles in the area, officials said.

Neither local nor federal officials had precise figures for added security costs, but Boyer said overall expenses related to parade protection alone would likely exceed $1 million.

(Reporting by Steve Gorman; Editing by Sara Catania and Cynthia Osterman)