The Federal Aviation Administration will ban drones and other aircraft above Philadelphia during Pope Francis' two-day visit there next month as part of security measures being put in place.
The ban also includes model airplanes, gliders and planes towing advertising banners on Sept. 26 and 27, when the pope is scheduled to tour the city and say Mass outside the Philadelphia Museum of Art.
"The restrictions are designed to provide a safe and secure environment for the event but also ensure fair and equitable access to all airspace users to the greatest extent possible," the FAA said in an advisory.
The U.S. Department of Homeland Security requested the ban, according to the FAA advisory, which did not indicate what security risks drones or other aircraft could pose.
Pope Francis is also scheduled to visit New York City and Washington, D.C., during his tour of the United States, which begins Sept. 22.
"We will be issuing the flight advisories for N.Y. and D.C. soon, and we expect them to mirror the advisory for [Philadelphia]," Kathleen Bergen, an FAA spokeswoman, said Tuesday.
A no-drone zone within a 15-mile radius of Ronald Reagan Washington National Airport in Washington, D.C., has been in effect since the 9/11 terrorist attacks. Only aircraft authorized by FAA and the Transportation Security Administration are allowed to fly in the restricted airspace.
Drones and other unmanned and unmarked aircraft aren't allowed to fly more than 400 feet off the ground, within 5 miles of an airport or near stadiums or people. Violators may face fines and criminal penalties.
Encounters with drones are climbing, with some spotted flying dangerously close to commercial aircraft and in restricted airspace over the nation's capital, raising concerns they could collide with passenger planes or be used as weapons.
So far this year, pilots have reported to the FAA more than 700 close encounters with drones, including more than 70 in New York State, some near Kennedy and LaGuardia airports.
The latest sighting occurred Aug. 18 when a JetBlue pilot landing an Embraer regional jet at Kennedy saw a white unmanned aircraft to his left cruising at about 700 feet.