As the Sri Lankan military closes in on the remaining core of Tamil Tiger rebels, there is growing concern about the fate of civilians trapped in the conflict zone. The government, guerrillas and human rights groups trade accusations over who is responsible for the lives of thousands of noncombatants unable to flee the fighting. A humanitarian disaster is in the making.

A powerful offensive by the Sri Lankan military appears to have broken the back of the 25-year-old Tamil insurgency that has claimed more than 70,000 lives. It is estimated that as many as 250,000 civilians — the government says 120,000 — are trapped in the 300 sq. km area to which the rebels have retreated. The government says the civilians are being held by the Tigers as human shields. The rebels counter that the government is not letting civilians go; a little more than 100 have fled since the military warned of a final assault and guaranteed safe passage to noncombatants for 48 hours.

No matter which estimate is correct — and independent verification is impossible as the government has, in keeping with long-standing practice, banned journalists and aid workers from accessing the combat zones — a final battle could yield a horrific toll. Both sides have been largely indifferent to the fate of noncombatants. The Tigers have long been accused of using civilians as shields or forced labor, while the military has accepted collateral damage as a necessary part of war.