BOMBS ROCK IDAHO CITY TORN BY STRIFE OVER RACISTS

Three bomb blasts rocked downtown buildings here today, including one housing a Federal Bureau of Investigation office, and the Federal authorities began an intensive investigation.

No one was injured and damage was not extensive. But some officials feared that the bombings, along with a similar one two weeks ago at the home of a human rights activist and the mailing of a pipe bomb to a Federal judge in North Dakota in August, might be part of a neo-Nazi terrorist campaign.

Coeur D'Alene, a logging town of 20,000 people, lies just south of the compound of the anti-Semitic group Aryan Nations, and the town has been a center of opposition to the group.

The three blasts this morning occurred within minutes in front of the Federal Building, at a chain restuarant and a downtown luggage store.

Another, unexploded bomb, a tin can wrapped with duct tape, was found on the roof of a military recruiting office across the street from the Federal building. Within minutes of the explosions, a caller warned The Coeur D'Alene Press that ''lives are at stake here; you're next.'' Court and City Hall Evacuated

A similar threat was phoned to the offices of the town's largest employer, the Coeur D'Alene Mines. Both businesses, along with public facilities that included the Kootenai County Courthouse and the Coeur D'Alene City Hall, were evacuated, but bomb squads found no other explosives.

On Sept. 15 a pipe bomb, reportedly rigged with shrapnel and hidden in a garbage can, blew out a wall at the rectory home of the Rev. William Wassmuth, a Roman Catholic priest who is head of the Kootenai County Human Relations Task Force. Father Wassmuth has been an outspoken opponent of neo-Nazi activities, and was the principal organizer of a rally in opposition to the World Congress of Aryan Nations, held here this summer.

Aryan Nations is the secular arm of the Church of Jesus Christ Christian at Hayden Lake, Idaho, which teaches that Jews are the offspring of Satan and should be exterminated.

The organization is the parent group of the Order, a paramiltary neo-Nazi band. Some of the Order's members have been convicted of counterfeiting, armed robbery and murder in the cause of a racial war against the Government, which the group maintains has been taken over by Jews. Aryan Group Denies Involvement

The Rev. Richard G. Butler, the 66-year-old head of the Ayran Nations and minister of the Church of Jesus Christ Christian, denied any involvement by his group in the bombings today, and maintained that they were a ploy ''to point the finger at us.''

Federal investigators, including both the F.B.I. and the Bureau of Alcohol, Tobacco and Firearms, said they had no evidence to link the bombings to any specific individuals or groups, but said the possibility of racist terrorism was under scrutiny.

Beyond the description of the unexploded bomb found on the roof of the Federal Building, investigators said they had no immediate information on the construction of the bombs today.

Besides the assault on the home of Father Wassmuth, another homemade pipe bomb was discovered in a package mailed to Federal District Judge Paul Benson in Fargo, N.D., Aug. 20.

A few days earlier, another such bomb exploded in the Fargo Post Office, causing minor injuries to employees. The authorities would not discuss any similarities to the bombs in the Coeur d'Alene incidents.

Judge Benson has tried several cases of anti-tax protesters, and was the presiding judge in the case of Gordon Kahl, convicted with three others of the murder of two Federal marshals. Mr. Kahl himself, a member of a extremist group called Posse Comitatus, also linked to Aryan Nations, was killed in Arkansas in a shootout with the Federal authorities.

Officers armed with shotguns patrolled the streets in Coeur D'Alene after the bombings today, and local school and public buildings in nearby Spokane, Wash., were placed on alert.