SALT LAKE CITY — A conservation organization is suing the U.S. Department of Interior for offering oil and gas leases in a remote section of southeast Utah it says is packed with ancient cultural relics.

Advocates for the West filed the lawsuit Wednesday in U.S. District Court in Utah on behalf of Friends of Cedar Mesa, which is targeting the first of three related oil and gas lease sales held in March 2018.

The parcels are in an area between Canyons of the Ancients and the former boundaries of the Bears Ears National Monument that the conservation organization says contains dozens of ancient community centers and Chacoan Great Houses that are larger than the largest archaeological site documented at Bears Ears.

Josh Ewing, executive director of Friends of Cedar Mesa, said his organization has worked with federal land managers but they have refused to remove any of the sensitive parcels from potential leasing.

“For an on-the-ground organization focused on stewardship and working constructively with government agencies, going to court is an absolute last resort for us,” Ewing said. “However, if we don’t stand up for these lands and cultural sites, no one will."

Ewing asserts the government is tying its analyses of two subsequent sales to the March 2018 sale. Between the three sales, more than 76,000 acres of land will have been leased on 44 parcels of culturally rich lands, he added, noting the federal government has acknowledged the existence of 1,700 archaeological sites. The lawsuit contends more than 900 sites in the area are eligible for listing on the National Register.

The leases from the March 2018 sale, although bid on, have not yet been issued because the Bureau of Land Management has to resolve any protests.

Don Simonis, a former archaeologist for the Bureau of Land Management, said the area is rich with sites sacred to indigenous people.

"In many of these lease parcels, less than 10 percent of the lands have been surveyed; so the recorded sites the BLM knows about are just the tip of the iceberg," Simonis said.

Before any industry activity occurs on a parcel, the Bureau of Land Management must conduct an environmental review that includes an analysis of potential impacts. That review would also include a survey of a cultural sites.

Ewing said those next steps are inadequate.

"The requirements later have loopholes in them large enough to drive bulldozers through. Without a more comprehensive landscape-scale planning effort, the leasing phase is the last chance for the BLM to be smart from the start and take a comprehensive look at the impacts of development to a landscape of incomparable density of cultural resources."