General Gregory Guillot's reassurances came as the joint US-Canadian North American Aerospace Defense Command (NORAD) reported that Santa and his reindeer were making stops in Russia and Iran after visiting countries further east including Japan, North Korea and Indonesia.

Santa's journey this year comes after weeks of mysterious sightings of alleged drones in the US state of New Jersey, sparking worldwide curiosity even as many of the reported incidents were debunked.

"Of course we are concerned about drones and anything else in the air," NORAD commander Guillot told Fox News. "But I don't foresee any difficulty at all with drones for Santa this year."

NORAD's Santa tracker dates to 1955, when a Colorado newspaper advertisement printed a phone number to connect children with Santa -- but mistakenly directed them to the hotline for the joint military nerve center.

The director of operations at the time, Colonel Harry Shoup, answered the phone and quickly realized the child calling had the wrong number.

"But (he) didn't want to upset him. So he started talking to the young child and passed along information" on Santa's location, Canadian Air Force Major-General William Radiff, NORAD's current director of operations, told AFP on Tuesday.

"And then afterwards, he talked to the rest of the staff there and said, 'please, we're going to get phone calls today... Let's start doing this.'"

- Calls from around the world -

The interest has gone global. Last year NORAD's modernized Santa tracker website noradsanta.org -- which includes a 3D map displaying Santa's movements in real time and a ticker showing how many presents have been delivered -- had 20.6 million visits, and more than 400,000 calls were made to the toll-free number, according to Radiff.

"We get calls from all across the world and they really want to know where Santa is," he said.

When not spreading holiday cheer, NORAD conducts aerospace and maritime control and warning operations -- including monitoring for missile launches from North Korea, something perhaps on Santa's mind as he guided his reindeer-hauled sleigh over Pyongyang.

Radiff, embracing the Christmas spirit, said NORAD's infrared-capable satellites could monitor Santa's progress in part because "Rudolph's nose gives off the same signature, so we use that to track him around the world."

NORAD "always does a fantastic job helping us keep tabs on Santa's navigational heading and bearing in the skies above," astronaut Buzz Aldrin, the second person to ever walk on the Moon, said on social media.

Last Christmas, US President Joe Biden joined in the fun at NORAD, taking calls from children.

As of midday Tuesday US time, some 2.5 billion presents had been delivered, according to NORAD.