SEAR 1 events are “reserved for events of the highest national significance and enable the federal government to provide the full range of law enforcement and security resources necessary to support local officials in ensuring a safe and successful event,” the DHS official said, per the outlet.

President Donald Trump and several cabinet members are expected to attend Sunday’s service at State Farm Stadium, home of the Arizona Cardinals. Secret Service Special Agent William Mack, who leads the Phoenix field office, said the agency has been designated as the federal coordinator for the funeral.

“Our teams are already on the ground in Phoenix and Glendale, working side-by-side with state, local, and federal partners,” Mack told reporters. “Together, we are fully committed to ensuring that these solemn events receive the comprehensive protection and support they require.”

Local law enforcement assisting with the service will include officers from the Glendale, Arizona, Police Department. “We will not be surprised if more than 100,000 people show up,” said Jose Santiago, public information officer for the Glendale Police Department.

Officials expect mourners to travel from across the country, with some likely lining up for the first-come, first-served service as early as 2 a.m. Sunday. Parking will open at 7 a.m. local time, and camping in the area will be prohibited.

“Officers will be anywhere the eye can see, and in places it can’t,” said Santiago, referring to aircraft, many drones in the air and helicopters at the ready. The Department of Public Safety and the Secret Service will oversee security operations inside State Farm Stadium, home to the NFL’s Arizona Cardinals.

The funeral is open to the public, but those who plan to attend are asked to register with Turning Point USA, ABC News reported.