KABUL, Afghanistan —  Suspected Taliban terrorists opened fire on a checkpoint in southern Afghanistan early Friday, killing one policeman and wounding three, an official said.

Two militants died in the two-hour gunbattle that followed the attack, launched at around 2 a.m. in southern Helmand province's Dishu district, said deputy provincial governor Amir Mohammed Aghulzada.

Earlier this week, police and anti-narcotics forces launched a major opium eradication campaign in Helmand, the top drug-producing province in Afghanistan, plowing up poppy crops with tractors in Dishu.

Authorities suspect Taliban militants are implicated in the trade, but Aghulzada said Friday's attack appeared unrelated to the anti-drug effort.