BOSTON: When it comes to fears about a terrorist attack, people in the US usually focus on Osama bin Laden and foreign-based radical groups. Yet researchers say domestic extremists who commit violence in the name of their cause — abortion or the environment, for example — account for most of the damage from such incidents in this country.

These home-grown groups are seven times more likely than overseas groups to commit some kind of violence in the United States, a panel reported on Sunday at the annual meeting of the American Association for the Advancement of Science.

In many ways, actions by these domestic extremists can be termed “terrorist” cases, the researchers indicated. “The typical ‘terrorist’ is an alienated guy, usually a young male,” said Brian Forst of American University in Washington.

“They take comfort in like-minded souls and develop an idea they think will make a splash,” he said. They do not always carry it out, but sometimes they do, he said. “They are not lunatics.”

More research is needed into these domestic extremists and what leads them to commit violence, said Gary LaFree of the National Center for the Study of Terrorism and Responses to Terrorism in College Park, Maryland.

“It’s just as important to understand the bomb-maker as it is to understand the bomb,” he said.

That is what Kelly R Damphousse of the University of Oklahoma has been working on — where the extremists live and work, where they meet and build their weapons and where and when they strike.

Damphousse said right-wing extremists spend the most time meeting, preparing and planning before committing a violent act — some 480 “events,” whether that is a telephone call or some other form of plotting.

On a smaller scale are environmental activists who commit violence. On average, it is just 59 preparatory activities, he said.

“Environmentalists don’t need much. They need a spray can. They need a match. They don’t have to build a bomb,” Damphousse said.

Often, he said, they are simply frustrated by the political process and decide “let’s go do something”.

While some domestic extremists travel long distances, most strike within 30 miles of where they live, Damphousse said. Environmental extremists tend to strike within 10 miles of home.

Tuesday is the most common day for an attack, he said. Right-wing extremists tend to be early risers, striking in the morning, he said, while left-wing activists wait until evening and environmentalists wait until after midnight.

David Caspi of the John Jay College of Criminal Justice in New York said domestic extremist groups tend to fall into three categories — political, religious and youth culture:

— Examples of religious-based include the white-supremacist Aryan Nation, founded in Idaho, and the Oklahoma Constitutional Militia, an anti-government, anti-Semitic group; both are now closed down.

— The National Alliance was a political based white supremacist group, he said.

— An example of a youth group still operating is PEN1, standing for Public Enemy Number 1, which grew out of the punk rock culture to become a white supremacist group, he said.

Forst said researchers need to learn more about what contributes to the longevity and lethality of such organisations, noting that domestic extremists have far greater access to the United States than those from abroad.

Damphousse noted that researchers have compiled an international Terrorism Knowledge Base — http://www.tkb.org — listing incidents around the world.

The section on the United States lists such organisations as Animal Liberation Front, Environmental Liberation Front, Anti-Castro Cubans and the Black Revolutionary Assault Team among others.—AP