US President Donald Trump has attacked department store Nordstrom that this week decided to stop selling Ivanka Trump’s clothing and accessory line, for treating his daughter “unfairly”.

“My daughter Ivanka has been treated so unfairly by @Nordstrom. She is a great person — always pushing me to do the right thing! Terrible!” Mr Trump posted on Thursday.

President Trump then retweeted the missive from the official presidential Twitter account, drawing criticism from those who felt he shouldn’t use the @POTUS account to air personal interests.

My daughter Ivanka has been treated so unfairly by @Nordstrom. She is a great person — always pushing me to do the right thing! Terrible!

— Donald J. Trump (@realDonaldTrump) February 8, 2017

White House Press Secretary Sean Spicer defended Mr Trump’s behaviour, saying the president had “every right” to defend his family.

“When it comes to his family, he’s been very clear how proud he is of them. For someone to take out their concern with his policy on a family is not acceptable.” Mr Spicer said in a press conference on Wednesday (US time).

CNN anchor Bill Weir tweeted that according to a White House schedule, the tweet was sent “20 minutes into his daily intelligence briefing”.

Nordstrom shares dropped after the tweet but later recovered.

The department store chain last week said that it made the decision based on the brand’s performance, and that each year it replenishes about 10 per cent of its supply with new products.

In a statement to The Daily Beast on Thursday, the retail company reiterated that it had dropped Ivanka’s line based on performance.

“Over the past year, and particularly in the last half of 2016, sales of the brand have steadily declined to the point where it didn’t make good business sense for us to continue with the line for now,” the statement said.

“We’ve had a great relationship with the Ivanka Trump team. We’ve had open conversations with them over the past year to share what we’ve seen, and Ivanka was personally informed of our decision in early January.”

The ‘Grab Your Wallet’ campaign

A social media campaign called Grab Your Wallet had previously urged a boycott of stores that stock Ivanka Trump or Donald Trump products, including Nordstrom.

However, following Mr Trump’s condemnation of the department store chain, supporters of the campaign urged their followers to reward Nordstrom’s efforts by returning to shop there.

https://twitter.com/puppymnkey/status/829382912239890434

In November last year, Ivanka Trump said she would take a leave of absence from her clothing and accessories business as well as the Trump organisation.

Last week, Rosemary K. Young, senior director of marketing at Ivanka Trump, said the brand is expanding and had seen “significant” revenue growth last year compared with the previous year.

The New York Times reported other retailers were also taking moves against Ivanka’s brand.

It said department store Neiman Marcus has “changed its relationship” with the brand, but Ms Trump’s clothing is still sold at Macy’s, the nation’s largest department store, as well as its sister company, Bloomingdale’s, where her shoes and handbags are available online.

Trump’s tweet ‘unprecedented’

A spokesman for the watchdog Citizens for Responsibility and Ethics in Washington said Mr Trump using his position to attack Nordstorm was “unprecedented”.

“It’s pretty rare for the president to use the power of the presidency to go after a company. And to do so on behalf of his family’s business interests is certainly something we’ve never seen before,” Jordan Libowitz told the New York Daily News.

Former US president Harry Truman fired off a scathing attack in defence of his daughter on White House letterhead. Photo: Getty

Only one other president has ever done something similar – in 1950 then-president Harry Truman fired off an angry letter – using the White House letterhead – slamming a critic who had given his daughter a bad review after a recital.

Mr Truman took aim at The Washington Post‘s music critic Paul Hume for writing that his daughter, Margaret Truman, “cannot sing very well”.

In response, Mr Truman wrote a not-so-subtle threat to Mr Hume: “Some day I hope to meet you. When that happens, you’ll need a new nose, a lot of beefsteak for black eyes, and perhaps a supporter below!”

Mr Hume was unperturbed and later reconnected with the retired president, while Margaret Truman gave up her singing career to write murder mysteries.

– with AAP