"The organisation is asking a federal court in Washington DC to halt construction on the addition until the White House "complies with the law by going through the legally mandated review processes", including a public comment public period, according to a statement.

"The White House is arguably the most evocative building in our country and a globally recognized symbol of our powerful American ideals," said Carol Quillen, President of the National Trust for Historic Preservation, a nonprofit organisation created in 1949 with a congressional charter.

The group said it was "compelled" to go to court after the White House ignored concerns it raised in October.

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In the lawsuit, the group argues that the White House broke the law by beginning construction without filing plans with the National Capital Planning Commission, by not seeking an environmental assessment of the project, and by declining to seek authorisation from Congress.

It also alleges Trump is violating the US Constitution, "which reserves to Congress the right to dispose of and make all rules regarding property belonging to the United States".

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The WH responded: "Nu-uh!".