Tamil Tiger Trap

Not even the United Nations can stand in the way of the Sri Lankan army now. Looking to finish off the Tamil Tigers, the government has ordered the few aid agencies still in the northern war zone to leave, saying it can't guarantee their safety.

Asia's longest-running civil war has left many claims of imminent victory in its wake, along with an estimated 70,000 dead. The difference today is that Tiger losses on the battlefield are compounded by high-level defections, and a stranglehold on the fundraising and smuggling operations that have sustained them.

In January, the government abandoned a truce and pledged to defeat the Tigers by the year's end. It has poured $1.5bn (£840m) into a multi-front offensive. The Mannar peninsula was reclaimed in July; forces are driving up east and west coasts to cut off a vital sea supply line from India, spearheaded by "deep penetration" units - armed plain-clothes agents - tasked with spying and sabotage. President Mahinda Rajapaksa, riding a swell of Sinhalese nationalism, insists his forces will not turn back "until every inch of land is recaptured and every terrorist is killed or captured".

The Tigers have lost more than 6,300 fighters and three-quarters of their territory, according to the country's ministry of defence. Claims and counterclaims are a staple of the propaganda war, but even the Tigers admit they have lost ground. Generals say they are within artillery range of the political capital, Kilinochchi, where the guerrilla leader Prabhakaran is believed to be holed up.

This is bad news for the 145,000 displaced native Tamils, now without help from the aid agencies, and the UN has warned that their number could surge above 200,000. For all its aggression, the government wants to avoid being accused of killing relief workers, as happened after the August 2006 massacre of 17 employees of a French aid agency.

At the same time, rights groups charge the Tigers with once again forcibly recruiting women and children to boost their ranks. They also allege that civilians will be used as a human shield at Kilinochchi. "The rebel military installations and civilian areas are mixed," says D B S Jeyaraj, a defence analyst. "If the army advances and confines the rebels into a smaller region, then civilian vulnerability will increase."

Kilinochchi has been in government hands before, only to be reclaimed by the Tigers in 1999 when they reversed army gains in just days. This time, however, they are without the former eastern commander Colonel Karuna Amman. He split from the rebels in March 2004 and took 6,000 cadres with him, cutting the Tigers' ranks by as much as 60 per cent. Last July the Tigers were ousted from the east, a long-time bastion.

Another former Tiger, Sivanesathurai Chandrakanthan, known as "Pillayan", was elected in May as chief minister of the eastern province, in a government down-payment on its promise of greater political power and economic prospects for eastern Tamils in exchange for support. On a recent afternoon in the port town of Trincomalee, the former child soldier presided over a meeting with four army generals. These men would once have killed each other.

But native villages are now off-limits and controlled by the army, and arrests and "disappearances" are common in urban areas. President Rajapaksa insists there will be "no peace and development" until the Tigers are defeated.

The Tigers' military setbacks are compounded by financial strains. According to Jane's Intelligence Review, they raised as much as $300m a year at their peak - mostly from abroad - giving them one of the highest budgets for a separatist group, second only to Colombia's Farc. But post-9/11, with the US and the European Union listing the Tigers as a terrorist group, dozens of financiers and arms smugglers have been arrested and millions in assets seized or frozen.

Observers note that the current offensive has yet to encounter the full weight of the Tigers forces. "The government has succeeded in significantly weakening the Tigers [but] they have a hardcore fighting unit that even by conservative estimates could run into several thousand," says Amantha Perera, a defence columnist for the Sunday Leader newspaper. In the past, the Tigers gave up territory to overextend army troops, he notes.

Karuna has said the Tigers may have chemical weapons they can deploy. Even if they are broken as a conventional fighting force, they could regroup in the dense northern jungles to wage a guerrilla war, Prabhakaran's speciality. And past experience dictates that when the Tigers are squeezed, terror becomes a useful tool. After a period of relative calm in the south, an explosion at a crowded Colombo market late last month wounded 45 people, a likely sign of more to come.

There is no doubt among watchers that a lasting peace will stay out of reach until the roots of Tamil nationalism are seriously examined. "Irrespective of what happens on the battlefield, what you will get is a military victor and not an end to the conflict," says Paikiasothy Saravanamuttu, director of the Centre for Policy Alternatives, a think tank in Colombo. "If not accompanied by a political strategy, we're not really out of the woods."