TERROR IN OKLAHOMA CITY : Experts Link Bombing to Militants Bent on Punishing U.S. Government : Investigations: FBI says tracking potential terrorists is a daunting job. Some are guided by foreign ideology, while others have ties to domestic hate groups.

Although the Oklahoma City bomber may yet turn out to be a madman with a grievance against the federal bureaucracy, terrorism experts are working on the assumption that the attack was the work of militants determined to punish the government for some element of its domestic or foreign policy.

The FBI regularly tracks potential terrorists, but their number has become so large in recent years that the most daunting task is sorting through the welter of information to differentiate between those who just talk and those who might act, U.S. officials said.

The typical terrorist is more dangerous today than he used to be and is a much more elusive quarry, FBI Director Louis J. Freeh told Congress recently.

“Today, acts of terrorism generally are more spectacular, are aimed at causing larger numbers of casualties and raise higher levels of fear among civilian populations than in the past,” Freeh said.

During the last few years, the FBI has conducted hundreds of counterterrorism investigations annually, both of international and domestic groups. But the vast majority--about 1,000--have been aimed at groups that are based or directed from abroad or are driven by foreign ideology compared to about 25 investigations of domestic terrorist organizations like the Ku Klux Klan and other hate groups.

But even though terrorists are often motivated by foreign ideology, Freeh noted in his testimony that foreign governments, for the most part, have not been directly involved in recent years.

“(Terrorist groups) operate in a decentralized fashion, unlike many state-sponsored groups, which tend to be more structured,” Freeh said. “The members move between different groups, factions, leaders and objectives based on evolving international or local conditions.”

The State Department was careful Thursday not to draw any connection to a foreign involvement in Oklahoma City. “At this point we have no information on a foreign link to the bombing,” said State Department spokesman Nick Burns.

And Jim Dempsey, an analyst at the Center for National Security Studies, cautioned that it is a mistake to assume the bombers are foreign. Although that remains a possibility, he said it is also possible that they represent some domestic hate group.

The surveillance of terrorist groups operating in the United States is made far more complex by the diffuse nature of American society. Unlike Israel, which focuses its counterterrorism efforts on Palestinian militants, the FBI cannot identify its targets by race or ethnic group.

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As the World Trade Center case in New York has demonstrated, Middle East tensions provide a motive for terrorists. But the United States--which has a worldwide reach as the center of capitalist and secular thought--is a magnet for terrorists with a broad spectrum of motives.

Freeh, in his congressional testimony, said one of the difficulties in tracking terrorists is that even if law enforcement officials know that someone is an active member of such a group, the U.S. government cannot make a move as long as the person does not engage in overt criminal activity.

But Dempsey said the FBI’s problem was not so much legal constraints as “the difficulty in sorting out the vast flow of information they receive.”

“They monitor and scrutinize an awful lot of people at a relatively superficial level and often do not press forward in narrowing down that large group to identify the few potential terrorists,” Dempsey said.

“It’s not a crime to talk,” he said. “There is a danger, which I think the FBI is aware of, that if you spend too much time concentrating on people who talk, you may miss someone making a bomb.”

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Although Oklahoma City might appear to be an unlikely site for what probably will become the most deadly terrorist attack in U.S. history, security experts say that city, along with Phoenix, Kansas City, Dearborn, Mich., Jersey City, N.J., and the Los Angeles area, are considered potential hotbeds for urban terrorism.

For example, John C. Gibbons, a counterespionage expert and former federal prosecutor, said a group called the Third World Congress of Hamas held conventions in Kansas City in 1990 and Phoenix in 1991, where they “promoted Islamic revolution and hatred for Israel and the United States.”

The acting head of the CIA, William O. Studeman, predicted Thursday that the pace of terrorism in the United States is likely to increase. He said the Oklahoma City bombing was an indication that terrorists are finding softer targets in response to improved security in cities like Los Angeles and New York.

“I think it is very worrisome,” Studeman said after a speech at Marquette University in Milwaukee. “It is the true globalization of the terrorist threat.”

Times staff writers David Willman and Ronald J. Ostrow contributed to this story.