Norad, the North American Aerospace Defense Command, has kicked off its 70-year tradition of tracking Santa Claus on Christmas Eve, with US President Donald Trump joining.

Along with First Lady Melania, Trump took calls from multiple children.

Every year, Norad tracks Santa as he circles the globe, with volunteers helping to answer calls and provide updates to children on his location.

The tradition started back in 1955, after a misprint in a department store led a young child to call a Colorado military command centre and ask for Santa's location.