WASHINGTON (Reuters) - President Donald Trump is set to visit Utah on Monday and is expected to announce his decision on whether to reduce the size of two national monuments where drilling and mining are banned, an administration official said on Tuesday.

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Trump is expected shrink the Bears Ears National Monument, set aside by former Democratic President Barack Obama, and the Grand Staircase-Escalante National Monument, preserved by former Democratic President Bill Clinton. The trip was first reported by the Salt Lake Tribune.

Trump has pushed to roll back regulations that prevent development. To that end, he had ordered a review of the size of 27 monuments: land with cultural, historical or scientific importance preserved from development by past presidents under the Antiquities Act.

Last month, White House spokeswoman Sarah Sanders said Trump would travel to Utah in early December, and U.S. Senator Orrin Hatch, a Utah Republican, said Trump would reduce the size of the monuments.

Environmental groups and Native American tribal organizations plan to protest Trump’s planned visit on Saturday at Utah’s state capitol at what they call “The Rally Against Trump’s Monumental Mistake.”

The announcement is expected to touch off a legal battle with environmental groups and Native American tribes. The Navajo Nation and the four other tribes that created and co-manage the Bears Ears monument plan to file a lawsuit the next day.

“We will be fighting back immediately. All five tribes will be standing together united to defend Bears Ears,” said Natalie Landreth, an attorney for the Native American Rights Fund.

The Southern Utah Wilderness Alliance and other conservation groups also plan litigation against the Trump administration to challenge changes to both Bears Ears and Grand Staircase, said Steve Bloch, director of SUWA.

Bloch said conservation groups are concerned that Trump’s announcement will include an order to offer areas in the monuments for public lease sales for coal mining or oil and gas drilling.

Industry groups like the oil lobbying organization the American Petroleum Institute have said in the past that both Bears Ears and Grand Staircase-Escalante were unfairly designated as monuments and needed to be reviewed.

Some Utah county officials welcome a reduction in the size of the monuments, which they say has restricted road access to protected areas.

In Kane County, where 60 percent of land is located within Grand Staircase, commissioner Dirk Clayson plans to attend Trump’s event if he is invited.

“We are grateful that somebody is listening to our local voice,” he said.