KABUL, Afghanistan - A NATO service member was killed yesterday in southern Afghanistan, where violence is increasing as the poppy harvest ends and the Taliban turns opium profits into payments for fighters.

In the southern province of Helmand, the world's leading opium producer and the Taliban's profit center, NATO officials say insurgents are regrouping and fighting to retake key cities and towns they lost during clearing operations by U.S. Marines during the past year.

In Sangin, where nearly a third of all British Afghan war casualties have taken place, Taliban insurgent commanders have retrenched and are answering U.S. Marines' latest offensives with stiff resistance.

"There is an attempt to take Sangin back," said Marine Maj. Gen. John A. Toolan Jr., commander of all U.S. and NATO forces in southwest Afghanistan.

Yesterday, a NATO service member was killed by an improvised bomb in the south, the coalition said. A day earlier, another coalition service member was killed in a roadside bomb attack.

NATO has provided no other details about the attacks or the identities of the dead.