Donald Trump plans to drastically cut national monuments, documents show.

President Donald Trump plans to shrink Bears Ears National Monument by 85 percent and reduce Grand Staircase-Escalante National Monument by half, according to documents obtained by The Washington Post that show the Utah sites would be cut more than administration officials signaled earlier.

Individuals briefed on the matter, who spoke on the condition of anonymity before a formal announcement, cautioned that some changes still could bemade before Trump makes his final decision public on Monday in Salt Lake City.

Trump will announce the changes to monuments established by former presidents Barack Obama and Bill Clinton, respectively, at the Utah Capitol. Themove will represent themost significant reductions by any president to designations made under the 1906 Antiquities Act, which gives the president unilateral authority to protect imperiled sites on federal lands and in federal waters.

The new proclamations, which also will split up both mon- uments into several smaller ones, would cut the overall size of Bears Ears from 1.35 million acres to 201,397 acres and Grand StaircaseEscalante from nearly 1.9 million acres to 997,490 acres.

Many Republicans, including Trump and state and local officials in Utah, have argued that previous presidents have abused their authority under the Antiquities Act by placing large areas off limits to industrial development, motorized vehicle use and other activities.

Trump signed an executive order in April instructing Interior Secretary Ryan Zinke to scrutinize any national monument larger than 100,000 acres that was established in the last 21 years. His administration, Trump said, would “end these abuses and return control to the people, the people of all of the states, the people of the United States.”

Zinke submitted a report to the White House in late August that proposed decreasing the size of at least four existing national monuments, plus changing the way a half-dozen more are managed.