Interior Secretary Ryan Zinke will make his recommendations about the future of the Bears Ears and Grand Staircase-Escalante National Monuments this week.
Zinke is reviewing the status of 27 national monuments and will make his recommendations known on Thursday. So far, Zinke has said he will leave six monuments intact, but that does not include Bears Ears. Zinke previously said he will recommend that Bears Ears be scaled down.
Trump has argued that previous administrations "abused" their right to designate federally protected monuments under the 1906 Antiquities Act and put millions of acres of land - mainly in western states - off limits to drilling, mining, logging and other activity without adequate input from locals.
Under the Antiquities Act, a president can declare certain areas of historic or scientific interest a national monument.
Conservation groups, state attorneys general and Native American tribes, including the five tribes which lobbied to create one of the sites under review - Bears Ears National Monument in Utah - have already said they plan to challenge any changes in court.
"We told Zinke that all the tribes are willing to go into battle in terms of litigation and we are here to fight for our monument," said Davis Filfred, a council delegate for the Navajo Nation council.