President Donald Trump has ordered signs to be placed outside the Smithsonian National Museum of American History, to caution visitors about exhibits his administration views as "inaccurate".

The order directs the Department of Interior to issue the warnings, and also to direct people about where they can find "accurate information regarding America's history".

The Trump administration has often accused the Smithsonian Institution, the world's largest research museum, as well as other academic organisations of harbouring an anti-American bias.

The Smithsonian did not immediately respond to the BBC's request for comment.

The order on Friday - titled Restoring Trust in the Smithsonian Institution - accuses museum leadership of not doing enough to celebrate America's founders on the country's 250th anniversary of independence, which took place on 4 July.

It says the museum's leadership team "views American history as a 'prime tool' to advance ideas of social justice and the radical transformation of our society".

An accompanying White House statement also accused the museum of veering "toward extreme political activism, rooted in Marxism, to divide, dispirit, and discourage Americans".

Democrats who oversee the Smithsonian condemned the order.

"This EO is a clear political overreach, driven by an ideological agenda to rewrite American history," congresswoman Melanie Stansbury, ranking member of the House Administration Committee, wrote on X.

"Our Smithsonian institutions do not belong to the President, but to the American people and so does our nation's history."

The executive order comes just days after Smithsonian director Anthea Hartig was grilled by Republican lawmakers in two congressional hearings, where the museum was accused of being "infected by a woke ideology that seeped into public displays, educational materials and planning documents".

Earlier this month, the White House Domestic Policy Council released a scathing report, claiming that the museum "erases our heritage".

Trump has set out to radically reshape American culture, which he says has been contaminated by "woke" left-wing ideology.

He has signed several orders that are intended to eliminate diversity, equity and inclusion programmes from the federal government - some of which led to legal challenges.

In March, he issued a separate order against the Smithsonian, directing it to "eliminate improper, divisive, or anti-American ideology".

The Smithsonian is largely funded by the federal government. Its museums offer free entry to some 15 to 30 million visitors each year. It operates 21 museums in Washington, Virginia and New York.

They include the National Museum of American History, the National Portrait Gallery, the American Art Museum, the National Zoo and more than a dozen others.