Super Bowl security plan informed by Paris attacks: U.S. official

Secretary Jeh Johnson said he and his team have been "constantly" in contact with security officials in Paris following the Nov. 13 attacks there by gunmen linked to the Islamic State militant group.

"The threat picture is different every February," Johnson told a news conference after he toured Levi's Stadium in Santa Clara, California, where the NFL championship game will be played.

"We are always informed by recent events and what we see in the world situation," he said.

Johnson and other officials who addressed reporters were tight-lipped on how the details of Super Bowl security plans might differ from previous years in response to the attacks in the French capital, and to a shooting rampage in December in San Bernardino, Southern California.

All the federal and local law enforcement officials who spoke stressed that there were no specific or credible threat at to the game, or to Super Bowl related-events in the region.

But they all also urged the public to stay vigilant, repeating the oft-heard motto "if you see something, say something."

San Francisco Police Chief Greg Suhr's department is policing events in so-called Super Bowl City in downtown San Francisco, 50 miles (80 km) northwest of Santa Clara. Suhr told the news conference his officers have made some arrests, but that they were all for people "having too much fun."

Police have kept a highly visible presence, with some officers wearing tactical gear and carrying assault-style rifles.

Santa Clara Police Chief Michael Sellers said his force was preparing for possible protests, adding there would be a designated area for demonstrations about a block from the stadium.

Jeffrey Miller, a senior NFL security official, said some 4,000 private security staff had been hired to support law enforcement at events and the game.

Fans cannot bring in backpacks, purses, coolers or a plethora of other prohibited items, and can expect pat downs and to pass through metal detectors, Miller said.

"While the level of security is high ... we strongly believe that our fans will be safe and should have no concerns after entry except rooting their team on to victory," Miller said.

(Reporting by Curtis Skinner in San Francisco; Editing by Daniel Wallis and David Gregorio)