WHILE the eyes of the nation are on Oklahoma City, the heart of much of the anti-government movement suspected of prompting the bomb blast there remains in the Northern Rockies and the Pacific Northwest.
The movement is becoming increasingly aggressive here, both in rhetoric and activities that officials say are dangerous and illegal. Some examples:
*Last month, seven militia activists were arrested in Roundup, Montana, for allegedly carrying concealed weapons and threatening county officials.
*In recent months, 16 people -- including the mayor of a small town -- in three Montana counties have been charged with ''criminal syndicalism,'' which is defined under Montana law as ''the advocacy of crime, malicious damage or injury to property, violence or other unlawful methods of terrorism as a means of accomplishing industrial or political ends.''
*Anonymous threats are increasing against judges, law enforcement officers, and other public officials.
The threats began well before the Oklahoma bombing. In recent days, there have been at least two bomb threats in Montana.
*Self-described ''constitutionalist'' and tax protester Calvin Greenup of Darby, Mont., recently called on some two dozen armed militia members to help defend his farm against overflights by a National Guard helicopter. Mr. Greenup threatened to shoot down the aircraft, which was on a regular training mission. Greenup, who has been charged with tax evasion, obstructing justice, and operating an unlicensed game farm, is considered a fugitive by local officials.
''This incident demonstrates the danger inherent in groups of paranoid, armed men roaming around thinking the government is out to get them,'' warns a recent report by the Montana Human Rights Network.
At a gathering in Post Falls, Idaho, last week just before the bombing, some 300 militia members and supporters heard featured speaker Eustace Mullins say, ''Rebellion is in the air, and I love it.''
''These groups are becoming more visible and bolder,'' Montana Gov. Marc Racicot (R) said in a Monitor interview Thursday at the state capital in Helena. Gov. Racicot is a former state attorney general who prosecuted several anti-government extremists here.
Militia members and sympathizers seem to be most concentrated in this sparsely settled region, where a frontier mystique and attitudes toward independence are especially strong. Legitimate opposition to the federal establishment is deeply rooted here, as exemplified by such things as the fight to take control of federal lands and support for Ross Perot in 1992 -- that was markedly higher than the national average.
The growth of militias is seen as the dark side of the so-called ''sagebrush rebellion'' or ''wise-use'' movement. But it is the potential for inciting violence that officials find most troubling.
''We have very serious concerns about any kind of activity that can erupt into illegal or threatening conduct that harms or injures or places other people at risk,'' Racicot says.
Among those threatened have been federal land managers in the West.
On March 31, a small bomb damaged a United States Forest Service office in Carson City, Nev. The device had been placed after working hours, and there were no injuries. A year earlier, a similar explosion damaged a US Bureau of Land Management office in Reno, Nev.
In some parts of the rural West, local officials are challenging the authority of federal employees. Those employees were recently issued ''contact cards'' that state: ''If you are confronted, detained, or placed in custody by state or local authorities, while engaged in or on account of your duties, cooperate, do not resist, and contact [the regional special agent].''
Some of the most radical militia movement members call themselves ''Freemen,'' even going so far as to declare their independence from the federal government. Others are known as ''constitutionalists,'' recognizing the authority of the US Constitution and Bill of Rights -- but no other laws.
Authorities are most concerned about constitutionalists who threaten local officials by putting bounties on them or issuing their own ''arrest warrants.''
''Their intent is to harass, intimidate, and terrorize anyone that steps in their way,'' prosecutor Nick Murnion told a Montana county jury in a recent case involving a ''Freeman'' convicted of criminal syndicalism.
While not all militia groups or members are overtly racist, experts say there is significant overlap between militias and white-supremacist or anti-Semitic ''Christian Identity'' groups. ''Racist extremists are actively involved or associated with militia organizations in at least nine states,'' the Klanwatch project of the Southern Poverty Law Center in Montgomery, Ala., reported in December. These states are Montana, Idaho, Florida, Colorado, Texas, Pennsylvania, Tennessee, Missouri, and Michigan.
Militia organizations here were quick to denounce and deny any connection with the Oklahoma bombing, in which the suspects now in custody have ties to the Michigan Militia. The Militia of Montana issued a statement in which the organization said it ''grieves with the families who lost loved ones in this attack on America.''
But John Trochmann, leader of the Montana group, told the Billings Gazette, ''I think someone in the shadow government did it.'' This, Mr. Trochmann described as ''the takeover government, including the United Nations.''
For years, conspiracy theorists have contended that international organizations are plotting to create a ''a New World Order'' that would usurp the nation-state established by the US Constitution.
Tim Bishop, staff leader of the Idaho-based Aryan Nations white-supremacist group, which held a skinhead youth meeting this weekend, says the Oklahoma bombing ''has nothing to do with us.''
While the most extreme opposition to the federal government is found in militias, similar attitudes can be found in more mainstream politics in this region.
''I think we must constantly be on guard that we don't allow bigotry or hatred to take over any official or unofficial movement,'' Idaho Gov. Phil Batt (R) said in a recent interview in Boise. But speaking of those wanting to assert state sovereignty and more county control, Governor Batt said, ''I understand where they're coming from.''