Santa Claus is coming to town.

The jolly happy soul packed up his sleigh and started his route around the world around 1 a.m. ET Saturday, according to North American Aerospace Defense Command (Norad).

For the 61st time, Norad was the official Santa Tracker, and was also answering the calls and questions from children around the world. The website followed Santa on his route and included a few videos of Santa flying through cities around the world.

Norad, a joint Canada-U.S. operation based in Colorado, said it kept up with Santa's swift pace by using a system of "SantaCams" and satellites with heat-sensing infrared sensors that can detect heat signatures from Rudolph's nose "with no problem," as the lead reindeer pulled the jolly old soul's sleigh across the sky.

<a href="https://twitter.com/hashtag/NORADTracksSanta?src=hash">#NORADTracksSanta</a> has reported sitings of <a href="https://twitter.com/hashtag/Santa?src=hash">#Santa</a> over Canada!!! <a href="https://t.co/timXbQsukk">https://t.co/timXbQsukk</a> —@NoradSanta

"The moment our radar tells us that Santa has lifted off, we begin to use the same satellites that we use in providing air warning of possible missile launches aimed at North America," Norad said on the FAQ section of its Santa website.

For any kids planning to try to sneak a glimpse of Saint Nick, Noradsaid it's impossible to predict exactly when he'll arrive at your house.

"Only Santa knows his route," Norad said. "We do, however, know from history that it appears he arrives only when children are asleep! In most countries, it seems Santa arrives between 9:00 p.m. and midnight on December 24th."

Royal Canadian Air Force CF-18s are now escorting <a href="https://twitter.com/hashtag/Santa?src=hash">#Santa</a> into Canadian air space!! Don't worry Santa, <a href="https://twitter.com/hashtag/WeHaveTheWatch?src=hash">#WeHaveTheWatch</a>! <a href="https://twitter.com/hashtag/NORADTracksSanta?src=hash">#NORADTracksSanta</a> —@NoradSanta

The first stop for Santa was in Russia. By 9 p.m. ET, Santa had already delivered over 4.5 billion gifts, starting in New Zealand and Australia, then navigating across much of Asia and into Europe. He is expected to arrive in North America later today.

Santa arrived in Canada at around 9:20 p.m. ET, escorted by Royal Canadian Air Force CF-18s.

"The responsibility of keeping watchful eyes over North American airspace 24/7 rests with our men and women of the Canadian Norad Region," said Maj.-Gen. Christian Drouin, commander of 1 Canadian Air Division/Canadian Norad Region, in a news release. "It is a duty and honour we hold dearly: to ensure Santa's safe passage through North America so he can deliver joy and goodwill this holiday season."

Curious kids can call Norad at 1-877-Hi-Norad or email Noradtracksanta@outlook.com to find out where Santa is headed next.

You can also follow the Santa Tracker on Twitter, Facebook and YouTube.