(UPI) Nearly two weeks after it was first discovered in the rural Utah desert, the mysterious object dubbed the "monolith" has disappeared, according to officials.

The Bureau of Land Management confirmed Sunday that the metallic tricornered beam found protruding from the earth in southern Utah was gone.

"We may not know if an extraterrestrial or Earthling installed the 'monolith' structure, but we can confirm that it has been taken by an unknown party or parties," the bureau tweeted late Sunday.

The bureau tweeted pictures of tire tracks near the monolith's former site and a triangle indent in the desert floor where it once stood.

It said on Saturday that it had received "credible reports" of its removal.

The three-sided, 10-12 foot beam was first sighted Nov. 18 by members of the Aero Bureau who were counting bighorn sheep from a helicopter, and its discovery garnered national and international attention and theories as to how it became planted in the public lands of Utah.

The bureau confirmed the installation's mysterious disappearance during a visit to the site on Saturday, explaining in a statement that someone over Friday night had removed the "illegally installed structure."

"The BLM did not remove the structure, which had been recently discovered on public lands in the Monticello Field Office," the statement read.

The BLM said it was investigating who was behind the installation when it was removed as development on public lands must be approved by the bureau and adhere to applicable laws.

"We recognized the incredible interest the 'monolith has generated worldwide," Amber Denton Johnson, the manager of the Monticello Field Office, which is responsible for the land where the structure was located, said in a statement prior to its disappearance. Many have been enjoying the mystery and view it as a welcome distraction from the 2020 news cycle. Even so, it was installed without authorization on public lands and the site is in a remote area without services for the large number of people who now want to see it.

Visitors who flocked to the monolith parked on vegetation and left "human waste" in the undeveloped area that lacks restrooms and parking lots, the bureau said.

It had requested that visitors not attempt to visit the site as it has no cell service and is only accessible to high-clearance vehicles, and an unknown number of passenger vehicles attempting to access the site had become stuck and required a tow, the Monticello Field Office said, adding that driving off designated roads is illegal.

"Whenever you visit public lands please follow 'Leave No Trace' principles and federal and local laws and guidance," Johnson said.

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