President Trump has decided to switch from the border wall to taking down the political wall that protects America’s national treasures. But does that mean national memorial sites dedicated to Black history are at risk?

At a Wednesday signing ceremony, Trump ordered federal officials to review two decades of national monument designations, calling them “another egregious abuse of federal power.”

The order reverses a previous order set by former President Obama and his predecessors that banned development on hundreds of millions of acres of federal land and water by creating monuments.

“Today I’m signing an executive order to end another egregious abuse of federal power and to give that power back to the states and to the people, where it belongs,” Trump said as he signed the order at the Interior Department, which oversees most monuments and must now undertake the review.

“The previous administration used a 100-year-old law known as the Antiquities Act to unilaterally put millions of acres of land and water under strict federal control. Today, we are putting the states back in charge. It’s a big thing,” Trump continued.

But under Trump’s new order, it is unclear if African-American national monument sites like those recognizing the Freedom Riders, a former school in South Carolina for freed slaves and the church where four little Black girls died in an Alabama church bombing — all designated as national monuments by Obama — could be at risk. But the review covers monument designations on 100,000 acres dating back to 1996.

According to The Hill, the order is aimed primarily at the Bears Ears National Monument, a 1.3 million-acre site in Utah that Obama designated in December that is sacred to Native American tribes. Obama’s order also prevented development like oil and gas drilling on the land.

Conservation groups like the Wilderness Society criticized Trump’s order. “This executive order calling for ‘review’ of national monuments designated under the Antiquities Act is an affront to every American who enjoys our national parks and historic sites, and an injustice to the future generations who should inherit them,” Jamie Williams, president of the Wilderness Society, told The Hill.

However, Trump’s allies supported the move and praised his efforts.

“The Antiquities Act is a century-old law that has been hijacked by executive overreach in recent years. While designating monuments is a noble goal, this law, like many others, has strayed far from its original purpose,” said Speaker Paul Ryan.

Under the Antiquities Act, presidents have nearly unlimited power to create national monuments on land the federal government already owns and can block oil and natural gas drilling, mining, grazing, fishing or other land uses, depending on the circumstances.

Former president Obama used the act to protect more land and water through the law than any other president.