Donald Trump makes no secret of his loathing for Democrats, border-crossers, climate-change advocates, China, NATO and the head of the US Federal Reserve and now he has added another name to his enemies list: Santa.

While taking calls from kids wanting to track Father Christmas’ progress towards their chimneys, Mr Trump was heard to tell a 7-year-old boy that believing in Santa at his age is “marginal”.

He listened for a moment when the call was piped through to the White House then said, “because at seven, it’s marginal, right?”

Mr Trump listened again and chuckled before saying, “well, you just enjoy yourself.”

The First Lady later tweeted that helping children track Santa was “becoming one of my favourite traditions”.

Watch Mr Trump’s call here

She told one caller that Santa was in the Sahara. Several minutes later, she reported that he was just touching down in Morocco but would be at the caller’s home on Christmas morning.

The young callers were part of the North American Aerospace Defence Command (NORAD) Tracks Santa program, a Christmas Eve tradition that started after a child mistakenly called the forerunner to NORAD in 1955 asking to speak to Santa.

The program wasn’t affected by the recent government shutdown and is run by volunteers at Peterson Air Force Base in Colorado using pre-approved funding.

The Trumps later travelled to Washington National Cathedral to attend the Solemn Holy Eucharist of Christmas Eve.

The cathedral’s website said the program included readings from Holy Scripture, favourite congregational hymns and seasonal choral and instrumental music as well as Holy Communion.

Mr Trump most likely would have been attending Christmas services at a church near his estate in Palm Beach, Florida.

But he scrapped plans to head to spend the holidays at his Mar-a-Lago retreat after parts of the government were forced to shut down indefinitely in a budget stalemate with Congress.

-with AAP