Terrorism, it is often said, is the "weapon of the weak". Groups that cannot win in conventional war use un-conventional means to strike terror behind the battlelines. Increasingly, however, the truly "weak" of society, specifically children, have been pulled into terrorism as targets and participants. The "soft" security issue of children has become one of the grimmest aspects of the "hard" issue of terrorism.

Despite global consensus against sending children into battle, there are 300,000 children under 18 (boys and girls) serving as combatants in almost 75 per cent of the world's conflicts; in 80 per cent of these, there are child fighters under 15, and in 18 per cent, fighters of less than 12 years old. It is no surprise therefore that, as on the world's battlefields, children are increasingly present in terrorist groups. Children offer terrorist group leaders cheap and easy recruits who provide new options to strike at their foes.

The fact that one of the first US servicemen to die in Afghanistan was shot by a 14-year-old sniper was little discussed in the media. US troops continue to face child soldiers in Afghanistan, the youngest on record being a 12-year-old boy captured in 2004 after a Taliban ambush. Equally, in Iraq, coalition forces are contending with the involvement of children in conflict. During the invasion that toppled Saddam Hussein's regime, American troops engaged Iraqi child fighters in at least three cities. The trend has grown during the insurgency with children serving as everything from snipers to front-line fighters in the fighting in Falluja.

Perhaps the most disturbing aspect of contemporary terrorism is the escalation of suicide bombing. Here, too, children are present. Groups such as Palestinian Islamic Jihad and Hamas have recruited children of 13 to be suicide bombers and as young as 11 to smuggle explosives and weapons. Youths have conducted more than 30 suicide bombings since the Israel-Palestine conflict revived in 2000.

Neither terrorism nor children's roles in it are a uniquely Muslim phenomenon. The Real IRA, a coalition of dissident IRA terrorists in Northern Ireland, began recruiting boys in the 14-16 age range in the late 1990s. Other examples range from Colombia, where the youngest reported terrorist was a nine-year-old boy sent by guerrillas to bomb a polling station in 1997, to Sri Lanka, where terrorists have used child suicide bombers.

In the war on terrorism, we are not simply facing groups of bearded men hiding in caves. To defeat terrorist groups we must deny them child recruits. It is essential to shrink the pool of potential resources and end terrorists' ability to access it. Underlying problems of hopelessness often lead children (and even their parents) to believe they have no better future than joining terrorism and its likely outcome of an early death. As Fadl Abu Hein, a psychology lecturer from Gaza, notes: "Martyrdom has become an ambition for our children. If they had a proper education in a normal environment, they won't have looked for a value in death."

Focusing solely on the leadership of terrorist organisations is not enough; it misses the larger socio-economic context that enables their recruiting techniques. An equally pressing problem is the environment of violence, humiliation and lack of opportunity that surrounds many children in troubled regions. This is heightened by failing education systems and economic stagnation across many parts of the world. Change these and we begin to change the present trends of terrorism.

Child terrorism does not happen through the spontaneous choice of the children themselves. We must undercut the institutions that assist terrorist groups in mobilisation and recruitment. Measures include enlisting religious leaders to speak out against the use of children; building up state school systems as an alternative to the private religious schools of hate to which poor parents are often forced to send their children; shutting down payment plans that reward suicide attackers and their kin; and holding not only leaders but also families responsible for their children's actions in order to create accountability beyond the child.

In battling against terrorist groups, we cannot simply hope to shame the shameless who think it acceptable to send a child to do their dirty work. But it is possible to make their job harder, undermine their support and eliminate their recruitment pipeline.