A pair of Senate Democrats are asking President Trump to explain why he is poised to remove protections of land managed by the U.S. Forest Service from the Bears Ears National Monument even though the agency did not recommend the change.

Sen. Debbie Stabenow of Michigan, the top Democrat on the Senate Agriculture Committee, and Sen. Michael Bennet of Colorado, say the contentious Bears Ears is one of five national monuments that Trump is seeking to shrink that have Forest Service land as part of their designation. The other four are in California: Berryessa Snow Mountain, San Gabriel Mountains, Giant Sequoia, and Sand to Snow national monuments.

“In advance of any decision to attempt to modify the boundaries of national monuments, we write to seek specific details regarding your plans for treatment of certain acres within five national monuments that are managed by the U.S. Department of Agriculture’s Forest Service,” the senators wrote in a letter Friday to Trump.

Trump is expected to visit Utah Monday to announce his decision to shrink Bears Ears, along with Grand Staircase-Escalante National Monument.

Interior Secretary Ryan Zinke recommended that Trump shrink Bears Ears, a 1.35 million-acre monument that former President Barack Obama designated in December, as part of an extensive review of national monuments made by recent presidents.

The Washington Post reports that Trump will reduce the size of Bears Ears by as much as 85 percent, citing draft maps prepared by the Interior Department.

Bears Ears has 289,000 acres of Forest Service land, and some of that would be affected under the maps, which are not final.

A national monument can include land overseen by multiple agencies, including land managed by the Forest Service under the Department of Agriculture, and the National Park Service and Bureau of Land Management under Interior.

Stabenow and Bennet say removing Forest Service land from Bears Ears or the other four monuments would contradict the agency’s recommendations to Zinke.

Trump ordered the Interior Department to undertake a review of 27 national monuments shortly after his inauguration. The administration says previous presidents abused their authority under the 1906 Antiquities Act to unilaterally declare national monuments, by setting aside larger and larger swaths of public land.

Bears Ears is perhaps the most contentious one Zinke pegged for a reduction.

Obama created the monument just before he left office, protecting a vast area of mesas and canyons in Utah's poorest county. It is an area in the southeastern part of the state that five Native American tribes consider sacred.

Zinke also proposed reducing the size of the 1.9 million-acre Grand Staircase-Escalante, which President Bill Clinton declared in 1996.

The Washington Post reported this week that Trump plans to divide Bears Ears and Grand Staircase-Escalante into new smaller monuments under different names.

Bears Ears would be divided into Indian Creek National Monument and the Shash Jaa National Monument.

Grand Staircase-Escalante would be split into three areas: Grand Staircase National Monument, Kaiparowits National Monument, and Escalante Canyons National Monument.

Environmental and conservation groups, as well as Native Americans, have promised to sue the Trump administration if it scales back the monuments.

Supporters of the monuments note the Antiquities Act does not explicitly give authority to presidents to reduce the size of national monuments, although some have done so on a limited scale. The concept has not been tested in court.