Security experts say terrorism will be a fact of life for the foreseeable future, and that governments and businesses must learn to manage the risk. The emergence of suicide bombers and rise of modern communications have created a new kind of conflict, which shows no signs of abating.

John MacGaffin watched the spread of terrorism for some 30 years in his former career as an officer with the U.S. Central Intelligence Agency. He is now president of the U.S. branch of the firm AKE, which provides security training for businesses, non-government entities and news organizations, including Cable News Network and Voice of America.

He told a Los Angeles business group that terrorist leaders Osama bin Laden and Abu Musab al-Zarqawi present an unconventional threat for Western governments and business.

"Both believe that they're engaged in a battle in which only one side, them or us, can win, that only one side is going to be left standing when this is all over," he said.

The conflict with Islamic militants is lopsided, says Mr. MacGaffin, because it is an all-consuming battle for the terrorists, who are unlikely to compromise for short-term gains. He adds that, unlike conventional forces, terrorists are agile and hard to detect. They are also hard to attack because their organizations are fluid, and can be rebuilt from a large pool of potential recruits.

The emergence of suicide bombers presents challenges not seen in earlier terrorist conflicts, says Andrew Kain, the founder of AKE. A former special forces instructor with the British military, he says the British experience in the enclave of Northern Ireland shows how difficult it is to root out terrorism.

"Population of 1.5 million, the Irish Republican Army or its groups drew support from about 10 percent of the population. At their height, they had perhaps 400 to 500 operatives," he reminded.

He says the separatist IRA did not conduct suicide attacks, as do Islamic extremists.

"Yet in 35 years, we were never able to stop the flow of weapons and explosives or prevent all attacks [in Northern Ireland]," he said.

The security expert says the war on terror must rely on special forces and intelligence, and international cooperation has become crucial. He says this is true for businesses, as well as governments, which need intelligence about the regions they work in, and must share information with others to spread the risk.

He says terrorists achieve much of their impact through publicizing their actions, and that they have successfully created the perception of a threat that exceeds the reality.

Michael Berkow, a deputy chief with the Los Angeles Police Department, worked with the U.S. Department of Justice in building police forces in Somalia, Haiti and elsewhere. He says terrorism becomes a threat when militant groups have both the motivation and the capacity to attack a target. He says this was true of al-Qaida until its operations were routed in Afghanistan.

"Right now, I think we've severely disrupted their capacity," said Mr. Berkow. "There are people that certainly have capacity, Hezbollah, Hamas, has tremendous capacity and, I would argue, probably have reach into the United States. They don't have the motivation to hit the United States."

The Palestinian group Hamas and Lebanon-based Hezbollah may have sympathizers in the United States, but focus their activities in the Middle East. These specialists say that groups like al-Qaida, on the other hand, target U.S. interests.

However, the terrorism experts say groups with the intention and the capacity to carry out attacks are likely to strike again inside the United States, as they did in 2001, and as they are doing today in other parts of the world.