US President Donald Trump set off a Christmas social media storm when during his Christmas Eve phone calls from the White House he questioned whether a seven-year-old was too long in the tooth to believe in Santa Claus.

But not to worry.

The child, Collman Lloyd, from South Carolina, who had called Mr Trump to find out where Santa was, told the Post and Courier newspaper she was still a believer.

She and her two siblings left cookies and milk out for Saint Nick overnight and, in the morning, the treats were gone and presents were under the tree.

Twitter had lit up after Mr Trump, capping a week of plunging stocks, a government shutdown and the US defence chief’s unceremonious departure, cast doubt on the cherished childhood fantasy.

“Are you still a believer in Santa?” Mr Trump asked Collman in a phone call. “Because at seven, it’s marginal, right?”

In a video her family posted on the internet, she replied “Yes sir,” later telling the newspaper she had no idea what “marginal” meant.

Mr Trump made the comment while taking calls from children calling the North American Aerospace Defence Command Santa tracker.

A Christmas tradition, the tracker delights children with “real-time” updates on his Christmas Eve journey.

“It’s just too freaking fantastic that Trump spent his Christmas Eve calling seven-year-olds and telling them believing in Santa at their age is ‘marginal,’” Democratic Senator Chris Murphy said on his Twitter account.

“Actually there is no heaven,” tweeted Dan Amira, head writer for The Daily Show with Trevor Noah comedy show. “When you die you just rot in the ground and get eaten by worms. Okay Merry Christmas, Timmy.”

The White House had no immediate comment on the social media response to the president’s Santa comments.

Stuck in Washington on Christmas morning because of the partial federal government shutdown, Mr Trump displayed little holiday cheer to reporters after a 20-minute video conference with US troops serving abroad.

“It’s a disgrace, what’s happening in our country,” he said. “But other than that, I wish everyone a very merry Christmas.”

@starrdust Do you believe in Santa and elves?

Originally Posted by stb2

@starrdust Do you believe in Santa and elves?

Santa didn't bring me an AK-47 so nope.

Originally Posted by starrdust

Santa didn't bring me an AK-47 so nope.

I also don't believe in Santa, because he didn't bring me you.

Originally Posted by stb2

I also don't believe in Santa, because he didn't bring me you.

Gheeeeey.

Santa said he'll bring you a gobble gobble named Zee.

Originally Posted by starrdust

Gheeeeey.

Santa said he'll bring you a gobble gobble named Zee.

Noooo, Santa, why do you do this to me.

Originally Posted by stb2

Noooo, Santa, why do you do this to me.

Stalker alert, take cover.

Originally Posted by starrdust

Stalker alert, take cover.

Oh crap, imma go hide in my basement!

Originally Posted by stb2

Oh crap, imma go hide in my basement!

On your sticky, hole ridden couch? Don't forget your TV and PC!

Originally Posted by starrdust

On your sticky, hole ridden couch? Don't forget your TV and PC!

Yup, I will also bring some food as it's better to stay longer to be safe!