(Adds details on government security precaution in paragraph 6)
By Jennifer Dobner
SALT LAKE CITY, May 8 (Reuters) - A pair of motorists in a pick-up truck brandished a firearm and flashed a threatening sign at a federal land management worker in Utah, officials said on Thursday, about a month after a widely-publicized armed standoff with a rancher.
There was no indication the suspects in the incident on Tuesday were connected to supporters of Nevada rancher Cliven Bundy in a dispute over $1 million in grazing fees and the larger issue of federal control over public lands.
"Threats against Bureau of Land Management employees will not be tolerated, and we are pursuing this matter with local law enforcement," said Megan Crandall, a spokeswoman for the bureau in Utah.
A BLM employee was driving an agency vehicle on Interstate 15 near Nephi, about 90 miles south of Salt Lake City when two motorists whose faces were covered pulled alongside him and made an obscene gesture, officials said.
The suspects pulled away but returned minutes later, flashing a gun and a hand-scrawled sign that read: "You need to die," officials said. The car's license plate appeared to have been covered with duct tape.
As a safety measure, the bureau is stripping logos from some agency vehicles, BLM Fillmore Field Office supervisor Eric Reid said, according to The Salt Lake Tribune newspaper.
The federal government controls huge swaths of land across the western states, which often prevents state and local governments from using it.
In recent years the conservative state's rights advocates have pushed for taking back public lands. In Utah more than 60 percent of all public lands are under federal control.
Frustration with the BLM has mounted across Utah. A coalition of Utah ranchers has sued the agency for failing to manage the wild horse population and one central Utah county has said it would conduct its own roundup if the BLM fails to act.
"This type of intimidation is unacceptable and must be dealt with immediately," Steven Horsford, a U.S. Congressman from Nevada, said in a statement. "Unchecked militia groups are setting a precedent for lawlessness in the American West, and it is repugnant that this menacing behavior is spreading." (Editing by Dan Whitcomb, Grant McCool, Eric M. Johnson and Clarence Fernandez)