A nonprofit has filed a lawsuit seeking ‌to stop US President Donald Trump’s bold blue renovation of a reflecting pool at Washington DC’s Lincoln Memorial.

The ‌lawsuit, filed by the Cultural Landscape Foundation, alleges the renovation violates the National Historic Preservation Act, a law passed by Congress in 1996 that outlines procedures for changes to historic properties.

It is the latest ‌in a string of court challenges to the former real estate developer’s efforts to remake Washington landmarks.

The nonprofit seeks an emergency order halting the Trump administration’s overhaul, which focuses on replacing ‌the pool’s “grey ‌stone” appearance ⁠with an industrial-strength coating in the colour of a blue swimming ​pool.

“The dark grey, achromatic basin was not incidental to the design,” the lawsuit stated.

“It was the design.”

Trump announced the renovation last month, saying “it’s going to be fantastic”. Photo: AAP

The case was brought against the Department of the Interior, the executive agency overseeing the renovation. It said Trump had “done more to make our nation’s ⁠capital a shining beacon than any other president ‌in ​the history of this country”.

Trump announced the project last month, saying “it’s going to be fantastic” and “really ​beautiful”.

As ‌the project got under way, his motorcade took an unannounced trip to see the project up ​close.

Trump has said he was motivated to go ahead with the renovation after a friend visiting from Germany criticised the condition of the reflecting pool.

“He said, ‘It’s filthy, dirty. ​The ​water is disgusting-looking. It’s not representative of ​the country’,” Trump said at a White ‌House event last month.

Some of Trump’s other projects in Washington, including renovations to the city’s golf courses and construction of a White House ballroom, have also drawn legal challenges.

On March 31, a federal judge blocked above-ground construction of Trump’s ballroom, writing that “unless and ​until Congress blesses this project through statutory authorisation, construction has to stop!”.

An appeals court ​later lifted the injunction, ⁠allowing construction of the ballroom to proceed while litigation continues.

-AAP