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.
The executive order declares the president's official office, which he has renovated, to be a national monument.
"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.
The order does not prevent future presidents from changing the decor of the famous room.
The document 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".
American presidents currently have the power to make some changes to the White House but large projects require the permission of Congress.
The order comes months after Trump tore down the entirety of the White House East Wing in a project that has faced legal challenges.
The project was not approved by the US Congress. Construction has continued, with plans to turn the space into a new ballroom.
Signing the new executive order on Thursday, the president said: "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."
He added that world leaders who have visited in recent months have complimented his decorative 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".