The NFL season is building up to its grand finale, Super Bowl 50, on 7 February where nearly 70,000 fans will fill the Levi's Stadium in San Francisco and millions will watch it around the world. Being one of the biggest sporting events on the planet comes with high security risks and the FBI has issued a warning of the dangers of a "hi-tech attack" against crowds at the event.

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A security memo from government officials was issued highlighting the discovery of multiple unsolved sabotages on fibre optic cables in the area as well as the threat posed from drones. The document was obtained by America's NBC News4 I-Team, who revealed the FBI and US Department of Homeland Security is investigating a series of unsolved incidents that could be connected to a "more complex plot", which could be carried out on the 2016 Super Bowl.

The records showed there were at least 10 fibre optic cables mysteriously severed in and around a 40-mile radius from the San Francisco 49ers' stadium over June and July 2015. Authorities speculate these could have been dummy attacks conducted by terrorists to identify vulnerability of the cables and to gain information on communications infrastructure ahead of a full-scale attack.

"It raises the concern individuals may be using these incidents to test and prod network durability in conjunction with a more complex plot," the document said.

The Stack claims the concern behind attackers targeting the network of fibre optic cables is mainly down to the fact they serve as back-up communication systems in emergencies and could slow down response times. Tapping into the fibre optic cables could also allow hackers to gather security intel in the lead-up to the Super Bowl as well as take systems offline.

Drone impact

The memo also raised the issue of drones posing a threat to crowds at the event with malicious operators open to using the unmanned flying vehicles during an attack or an unauthorised user to physically harm members of the public in the event of a crash.

"[Drones] may present a low-altitude hazard to aviation assets supporting the event, allow unauthorised video coverage of events, or pose a risk of injury to event-goers if an operator loses control of a [drone]," News4 reported.

With both of these adding to the wide-scale potential security risks at Super Bowl 50, the FBI believes the biggest threat comes from a "lone wolf" terrorist who is able to go undetected by authorities by blending into the crowd and carry out an attack.

However, despite the investigation into the suspicious fibre optic cable tampering, the authorities are keen to stress there is no reason to suggest there is any cause of concern over an attack. The memo merely serves as an "assessment" to the potential risks – risks that would be present at any sporting event.

NFL organisers and security issued a statement stating they have been operating at a higher level of security since the September 11 terrorist attacks. NFL spokesman Brian McCarthy said: "We have been working for more than a year with our law enforcement partners at the federal, state and local level in preparation for Super Bowl 50. We have an effective and comprehensive plan in place to make Super Bowl 50 a safe and exciting event for our fans."