US retail giant Walmart has removed anti-Trump merchandise following online boycott threats from the president's supporters.

The items, including baby clothes and shirts featuring the words "Impeach 45", were for sale on Walmart's online marketplace from a third-party seller.

The "Impeach 45" clothes are no longer on the site, but a large selection of pro-Trump items are still for sale.

Walmart said in a statement that it is reviewing its marketplace policies.

"These items were sold by third party sellers on our open marketplace, and were not offered directly by Walmart," a spokesperson told the BBC on Tuesday.

"We're removing these types of items pending review of our marketplace policies."

The company issued a similar statement when it came under fire last year for selling a shirt with the words "Rope. Tree. Journalist. Some assembly required", on its third-party marketplace.

Walmart's marketplace does still feature anti-Trump items from third-party sellers, but no products calling for the president's impeachment appear to be available.

Items both for and against President Barack Obama and former Secretary of State Hillary Clinton are also for sale.

Students for Trump chairman Ryan Fournier first tweeted about the anti-Trump merchandise on Monday.

Trump supporters took to Twitter with the hashtag #BoycottWalmart.

One Twitter user called for Walmart to "clean up" its act, saying as a "pro American company it is wrong to politicise and be anti-US President with any product".

But others called it hypocritical to remove anti-Trump gear while still selling pro-Trump items.