Explosives are strapped to the waist, security guards dodged and the crowd is suddenly all around. The bomb is detonated and at least one life, and maybe dozens, is extinguished. Such is the dream of the suicide bomber, chosen by terrorists to make the ultimate statement - that even living is worth giving up for the cause. An increasing number of people are living that dream. In the past week, at least 135 people - 30 of them suicide bombers - have been killed in attacks in Morocco, Saudi Arabia and the separatist Russian republic of Chechnya. Co-ordinated, synchronised suicide operations have become the terrorists' preferred weapon. The method was dramatically - and chillingly - used in the World Trade Centre and Pentagon hijackings on September 11, 2001. Then, last October, a man with explosives strapped to his body ran into a Bali nightclub, sending panicked tourists fleeing into the blast of a nearby truck bomb. Muslim extremists carried out all the attacks and, except for those in Chechnya, they have been connected by officials to al-Qaeda, the international terrorist network established by Saudi-born millionaire Osama bin Laden in the early 1990s. The suicide-bombing method is most associated with Islamic militants, although it has been used to express opposition to officialdom from Colombia to Sri Lanka. First used by the anti-Israel Hezbollah in 1983 and later adopted by Hamas, barely a week goes by in the conflict between Palestinians and Israelis without another young Arab taking his or her life and those of Israelis in the name of an independent Palestine. But suicide bombings are a political, rather than religious, weapon. The beliefs of Islamic militants are not held by the majority of Muslims, who say suicide bombings are sullying their religion. Islam is being used to justify terrorism, they argue. Saudi Arabia's leading Islamic scholar, Abdulaziz bin Abdallah al-Sheikh, said in April 2001: 'What you call suicide bombings in my view are illegitimate and have nothing to do with jihad [in the cause of God].' Bin Laden and his supporters believe jihad, or holy war, is justified because of perceived Israeli oppression of Arabs, American support of the Jewish state. The US-led conflicts in Afghanistan and Iraq are seen as being against Muslims rather than terrorists. The roots of suicide attacks lie in the biblical Samson, who used his strength to bring down a building on his enemies. In the 19th century, Russian revolutionaries carried sticks of dynamite into war, having put their affairs in order in the belief they would not be returning. Middle East terrorism expert Magnus Ranstorp, of the Centre for the Study of Terrorism and Political Violence at St Andrew's University in Scotland, said last week the method had since been adopted out of strategic choice by many terrorist groups around the world. Explosives were inexpensive and easy to come by. The most costly part of an operation was the logistics - providing safe houses and making preparations for the attack. Recruitment was a secretive process. Potential suicide bombers had to have an ability to be indoctrinated and stay calm under pressure. 'It's a process that takes time to cultivate and generate the right momentum,' Dr Ranstorp said. 'Counter-terrorism has pushed it underground in Europe, but elsewhere - especially in the Middle East - there are plenty of volunteers.' The methods used made preventing the attacks difficult, as Israel has found, despite having an almost hermitically sealed security environment. 'They have security guards outside restaurants or in crowded places, checking people wearing bulky clothing, and vigilant law enforcement,' he said. 'Suicide bombers follow the path of least resistance - they do surveillance, check security and go for the target that is surmountable.' Sri Lanka's Tamil Tigers had probably the most sophisticated approach, creating special vests, intricately planning attacks and making use of female bombers to attract the minimum attention. From the first Liberation Tigers of Tamil Eelam suicide attack on July 5, 1987, until a ceasefire with the government last year, hundreds of civilians were killed, including Indian prime minister Rajiv Gandhi, Sri Lankan president Ranasinghe Premadasa and opposition leader Gamini Dissanayake. The Sri Lankan Central Bank, World Trade Centre and Colombo's international airport were devastated by separate bombings. An expert on terrorism and the psychology of terrorist behaviour, John Horgan, said terrorist groups preferred suicide bombings because they were effective. 'Terrorist tactics are all about causing disarray and exploiting confusion and anxiety,' he said. 'The idea that someone could be capable of committing such an act sickens and appalls us. We only see the end result and not the time and effort taken to recruit someone and to plan such an operation.' Dr Horgan, a lecturer at Cork University in Ireland, said finding recruits was not as simple as anti-Israeli groups like Islamic Jihad and Hezbollah made out. Their propaganda made it appear most Arabs were willing to become bombers. In an attempt to make the role attractive, the groups had glorified the role to one of martyrdom and in the Palestinian territories, successful attackers were treated as heroes. 'It's in the vested interests of terrorist groups to have a very strong and high psychological premium on becoming a suicide bomber,' Dr Horgan said. 'It's seen as a position for the chosen few ... a sought-after position.' Hamas, the military wing of the Palestine Liberation Organisation, did not take volunteers as this could leave them open to spies for Israel. Instead, Hamas recruiters identified specific qualities in potential bombers, such as a non-obtrusive character. Extremists who marched with knives and guns in support of bin Laden were not the sort of people who would become suicide bombers. Women were often trained as suicide bombers to avoid suspicion in male-dominated societies. People with secretive, introverted lifestyles were preferred to those with outgoing characters. Dr Horgan said that as a result, it was difficult for security officers to identify attackers. 'Psychologists used to think that there was a profile of a suicide bomber,' he explained. 'Generally speaking, this was someone without a job or any prospects of attaining meaningful significance in his or her life. But that's changed, and suicidal terrorists tend to be quite heterogeneous and come from varying backgrounds.' Some had a direct experience of family victimisation. They were not loners in the sense they were isolated from society, but for various community, social and psychological reasons, terrorist organisations were careful about who they took on. Those with a family to support or single children were not recruited. Group attacks, as on September 11 or in Saudi Arabia and Chechnya, had become increasingly common because of the peer pressure placed on participants. If one terrorist went ahead with plans, the bonding created by the shared goal made it more likely the others in the group would follow. Those who backed out or were arrested were shamed within their communities. Suicide bombings frequently achieve their aims by killing the intended target. In the process, they focus the world media on the social, political or religious cause. At the same time, though, they are counter-productive. In many cases, suicide bombings result in massive public outrage that governments interpret as a mandate to crack down harder.