(CNN)The Philadelphia Eagles and New England Patriots have been working on their Super Bowl game plans for two weeks. Law enforcement has been planning security for Sunday's spectacle for two years.
Security faces 'herculean' challenges at Super Bowl
"I think we have done our best to think of just about every contingency, natural or man-made," said Minneapolis police Cmdr. Scott Gerlicher, overall public safety coordinator for Super Bowl LII. "The Super Bowl is just a massive operation and very complicated."
The Minneapolis Police Department is the lead agency for security. But the department of about 840 sworn officers will get help from dozens of law enforcement agencies -- federal, state and local -- because it is simply not big enough to handle the huge undertaking.
"Coordination at all levels is key," said Alex Khu, St. Paul special agent in charge for Homeland Security Investigations and federal coordinator for Super Bowl security. "There are so many moving pieces. No one agency can do this alone."
The venue, US Bank Stadium, is smack in the middle of downtown Minneapolis around businesses, residences and public transportation, the FBI said, noting the security challenges.
Events leading up to Sunday's game near the stadium have made establishing the perimeter and security zones "significantly more complicated," according to Richard T. Thornton, special agent in charge of the FBI's Minneapolis division. These include this week's Super Bowl Experience at the Minneapolis Convention Center.
There will be a bulked-up police presence with officers in tactical gear, bomb-sniffing dogs, choppers and fencing in and around the indoor fixed-roof stadium, which is home of the Minnesota Vikings.
Coping with the brutal cold has been a factor in coordinating event planning and security. The temperature outside the stadium is forecast to be around 3 degrees Fahrenheit at game time at 5:30 p.m. (6:30 p.m. ET).
The FBI said attendees will be prescreened at indoor locations, such as the Mall of America in Bloomington more than 11 miles from the venue, "so they won't have to wait outside the stadium."
Such prescreening at other locations "is a first for the NFL and the security plan," said Joseph Rivers, an assistant special agent in charge in the FBI's Minneapolis division.
Screening procedures will begin at the stadium more than four hours before the game, with authorities setting out an extensive list of what is allowed to be carried into the stadium and what is prohibited, the NFL said.
"To provide a safe environment and to expedite fan entry into the stadium, the NFL limits the size and type of bags that may be brought into the stadium. All items carried by spectators will be carefully inspected and potentially not permitted into the stadium," a statement said.
As at every Super Bowl, the FBI is the lead agency for counterterrorism efforts in the runup to and during the game.
It is making threat assessments for the Super Bowl by analyzing attacks at mass events, such as the May bombing at the Ariana Grande concert in Manchester, England, and the mass shooting in Las Vegas in October.
"We are facilitating the name checks and records checks for all the folks who are going to get credentialed," Rivers said. "That means volunteers, food vendors, private security people -- the number of individuals could exceed 30,000. That's a huge commitment from our office."
The Minneapolis-St. Paul region has unique concerns over the years -- the stabbing at a mall, the bombing of a mosque and fears over the influence of Somalia's Al-Shabaab, an Islamist movement in that African nation, on the large local Somali population.
"We actually bring experience -- some continuity and background -- to the planning cycle, which we're obviously willing to share, and that we work with our state and local partners on to transfer some of that knowledge and hopefully shortcut some of the planning process," Rivers said.
The US Immigration and Customs Enforcement's Homeland Security Investigations also is on hand to be on the alert of "the illegal manufacturing and sale of counterfeit goods" such as sports apparel.
Gov. Mark Dayton has authorized the National Guard to provide security, with more than 400 Minnesota National Guardsmen called up.
"This is what we do," said Maj. Gen. Jon Jensen, adjutant general of the Minnesota National Guard. "When the local community can't meet the public safety needs, they come to the Guard. We're their normal partner, we're a natural partner, and we're their preferred partner when it comes to filling in the gaps that they can't fill."
Thornton called the effort "herculean." He said the goal is "making sure that it is not only a safe event for everyone that attends and participates, but that it's an enjoyable event for them as well."