US President Donald Trump has signed an executive order that he says will prevent future presidents from making certain changes to the White House Oval Office.

Trump, a former real estate mogul, has drastically altered the look of the president’s official office during his second term, most notably with adding many gold features.

“We’re making it a national monument, and it will not be allowed to be touched by anybody, destroyed, ripped down by stupid people, in order to build something in a slightly different shape,” Trump told reporters on Thursday.

American presidents currently have the power to make some changes to the White House but large projects require the permission of Congress.

The executive order, which Trump signed on Thursday, declares the Oval Office to be a national monument, along with some of its surrounding rooms.

The document also says that it does not “restrict the President’s authority to redecorate the monument, select furnishings, or make ordinary operational and security modifications that do not substantially impair the monument’s historic structure or architectural character”.

“We like the Oval Office, and it’s a symbol, like the White House itself. It’s a symbol of our country and the greatness of our country,” Trump said, adding that world leaders who have visited in recent months have complimented his changes to the room.

Trump said the White House and the Oval Office had been in need of repairs before his changes, calling it “badly damaged”. He described broken windows, cracked walls and broken stone.

Many of the noticeable changes, though, were cosmetic, including a large gold plaque reading “Oval Office” outside the space, paving over the Rose Garden and adding a new helicopter pad.

Trump said the order would “make it impossible for anybody ever to destroy this incredible space”.

The executive order comes months after the president tore down the entire East Wing of the White House in a project that was not approved by Congress. It has faced legal obstacles since construction began on a new ballroom that will replace the structure.