While the FBI says it is constantly assessing security risks, it has identified no credible or specific threats against the tournament, co-Deputy Director Christopher Raia told NBC News. But federal law enforcement does expect security issues to emerge, he said.

“I think there will be some kind of security event,” he said. “I think what you have to understand is security events range from a fan who may have had too much to drink starting an altercation all the way up to a major terrorist attack.”

But Raia said fans and spectators should feel safe heading to the games. “This is an all-hands-on-deck for us in order to keep our Americans safe,” he said.

The FBI said it has cameras, radars, listening devices in its anti-drone arsenal that can allow law enforcement to electronically take control of an unlawful drone and direct it to a safer area. Unlawful drones can also be forced from the sky if circumstances warrant.

The FBI said it also respects the rights of drone owners and does not intend to impede them in areas where no restrictions are in place, but it can be hard to distinguish an enthusiast from someone with an intent to cause harm.

In training exercises, the FBI used its own drones to demonstrate how it can track a drone and alert the suspected pilot. A loud warning blared overhead: “This is the FBI! You have violated a no-fly zone. Land your drone immediately and await contact by law enforcement. Do it now. Attention! Attention! Please exit the area immediately. I repeat, please exit the area immediately.”

Raia said the FBI has a message for drone enthusiasts who may be tempted to use their aircraft to explore or take photos at or near World Cup events: “With all the capability we have now, we will find you and it will be a very uncomfortable day for you.”

“You could potentially go to jail and so my advice to them, plain and simple: Don’t do it.”

Raia said that law enforcement is well prepared for the event, which planners have compared to running dozens of Super Bowls at once.

“We are ready,” he said.