The summit has been designated a National Special Security Event, making the U.S. Secret Service responsible for coordinating security. At a media briefing Wednesday, officials described months of planning involving the Secret Service, FBI, FEMA, Miami-Dade, Broward and Palm Beach counties, the city of Doral, and regional transportation and airport authorities.

Mike Townsend of the Secret Service’s Miami field office said South Florida’s role as an international gateway helped make it a suitable host for a gathering of world leaders. Miami-Dade State Attorney Katherine Fernandez Rundle pointed to the region’s experience managing major events, saying, “We have done it. We’ve proven ourselves before.”

But officials said a summit involving heavily protected heads of state brings security demands different from those of large sporting events. Miami-Dade Sheriff Rosie Cordero-Stutz said the G20 presents “unique security challenges” compared with events such as the FIFA World Cup.

Officials have not released a full list of attendees. President Donald Trump has invited Russian President Vladimir Putin, according to the briefing account, and the summit could bring leaders from countries involved in ongoing conflicts.

Residents and visitors should expect road closures, traffic detours and restricted-access zones in and around Doral during the summit. Townsend urged people to plan ahead and follow instructions from public safety agencies. The City of Doral and Miami-Dade Sheriff’s Office are expected to share traffic and closure updates as the event approaches; officials cautioned that some security measures may be announced on short notice.