Federal officials said yesterday that a white-supremacist group, whose followers have been linked to several armored-car robberies, the slaying of a Denver talk-show host and assaults on federal agents, has 100 to 150 members and ties to two extremist prison gangs.

FBI agent Bill Baker said the group, which is based in the remote resort town of Hayden Lake, Idaho, on a 20-acre compound surrounded by barbed wire, is linked to the Aryan Brotherhood and the Aryan Special Forces, two white-supremacist prison gangs that are said to participate in loan-sharking, extortion and gambling and are suspected in the murders of guards and fellow prisoners.

The group is called the Church of Jesus Christ Christian and its action arm is known as the Aryan Nations, a paramilitary organization responsible for the church's political and proselytizing activities.

Baker also said that some of the Aryan Nations membership "is basically the same as that of the former Idaho chapter of Sheriff's Posse Comitatus," a militant tax-revolt group. One of that group's leaders, Gordon Kahl, was killed in a June 1983 shootout with authorities in Arkansas.

The Aryan Nations church, earlier known as the Emancipated Church of the White Seed, was started in the late 1970s by Richard Girnt Butler and, according to Baker, "advocates white supremacy and the elimination of members of the Jewish faith and the black race from society."

Baker said that violent activities by the group have intensified in recent months and that FBI agents and local law enforcement officers have been advised to use caution when dealing with current or former members of the group.

Officials said an intense investigation of the group was recently conducted by agents from the Federal Bureau of Investigation and the Bureau of Alcohol, Tobacco and Firearms; the probe concentrated on the states of Washington, Idaho and Montana.

Last Sunday, police in Denver said that ballistics tests confirmed that a .45-cal. MAC-10 machine gun found in the Idaho home of a former member of the Aryan Nations was the weapon used to kill outspoken radio announcer Alan Berg last June outside his Denver home.

Gary Lee Yarbrough, 29, who was chief of security for the Aryan Nations until he joined a splinter group about a year ago, is being held without bond in the Ada County Jail in Boise on charges of assaulting a federal agent.

He is accused in connection with an Oct. 18 shootout with an FBI agent near his Sandpoint, Idaho, home. When agents searched the home, they found the MAC-10 and four crossbows, 100 sticks of dynamite, plastic explosives, hand grenades, semi-automatic rifles, infrared night-vision scopes, gun silencers, booby traps, police scanners and 6,000 rounds of ammunition.

Berg, 50, who was Jewish, was a flamboyant and controversial talk-show host for KOA radio in Denver. He was often critical of the Ku Klux Klan and neo-Nazi extremist groups, and sometimes billed himself as "the man you love to hate."

"I didn't kill him," Yarbrough told the Rocky Mountain News. "I never heard of him before I heard about this watching television."

Yarbrough eluded authorities until Nov. 24, when he was arrested following a shootout at a Portland, Ore., motel.

Yarbrough's roommate there, Robert Jay Mathews, 31, managed to escape from 20 FBI agents surrounding the motel, reportedly shooting one of them, Arthur Hansel, twice in the leg.

Mathews, who had left the Aryan Nations to form a group called the White Aryan Bastion, died Dec. 8 in a fiery shootout with FBI agents on Whidbey Island, about 20 miles northwest of Seattle.

Agents had surrounded three houses on the southern tip of the island and taken four persons into custody. When Mathews refused to come out, agents bombarded the building with tear gas, and SWAT (Special Weapons and Tactics) teams twice tried to storm the house, but were turned away by heavy gunfire from automatic weapons.

After a 36-hour standoff, authorities fired a flare to illuminate the area; it went into the house, igniting the ammunition there. The ensuing explosions sent flames 200 feet into the air.

Searching the other two houses, FBI agents found two rifles, a shotgun, a 9-mm handgun, a sword, a police scanner and disguise items, including fake mustaches and two women's wigs.

Among those taken into custody on Whidbey Island were Randolph Duey and Ian Stewart. Court testimony by FBI agents has linked them to an unidentified bank robbery, three armored-car robberies in Seattle and "possibly a homicide in Colorado."

U.S. Magistrate Philip K. Sweigert refused to set bail for the two men last Friday, noting that a manual was found in Duey's possession that included a "declaration of war" on the "Zionist-infiltrated U.S. government" and called for elimination of the "liberal Jewish press."

Duey is also a former member of the Aryan Nations church who split, with Mathews and Yarbrough, to form the splinter faction.

Mathews, Duey, Yarbrough, Stewart and "persons unknown" have been charged with the $500,000 robbery of a Continental Armored Transport Inc. truck April 23 in a Seattle shopping center.

Law enforcement sources said they are suspects in a bank robbery and other armored-car robberies, including the July 19 robbery of a Brink's armored car in Ukiah, Calif., that netted $3.6 million.

At least three other men are being sought in connection with the Whidbey Island raid; the FBI has refused to identify them.

Before the raid, Mathews had written to the Aryan Nations group, predicting his death. "It is only logical to assume that my days on this planet are rapidly drawing to a close," he wrote. "I will leave knowing I have made the ultimate sacrifice to secure the future of my children."

Mathews said he was worried that his son "would be a stranger in his own land, a blond-haired, blue-eyed Aryan in a country populated mainly by Mexicans, mulattoes, blacks and Asians."

One of the more active members of Aryan Nations has been Louis Beam, a computer consultant who was a grand dragon, or presiding officer, of the KKK in Texas.

Aryan Nations has spread its gospel of religious and racial hatred on two computer bulletin boards, the "Aryan Nation Liberty Nets." Anyone with a home computer and a modem can dial into the Aryan Nations system to read denunciations of blacks, Jews, communists, civil rights activists and the U.S. government, which has been nicknamed ZOG, for Zionist Occupational Government.

The group publishes a monthly newsletter, "Calling Our Nation," and a book catalog containing such titles as "The Holy Book of Adolf Hitler," "The Negro: Serpent, Beast and Devil" and "Story of the Ku Klux Klan."