A roadside bomb in western Afghanistan killed three civilians and wounded 48 others including 10 children, officials said Thursday. The blast targeted a passing police vehicle in the city of Farah, killing the civilians, wounding 10 children and dozens of construction workers, said Mohammad Qasem Bayan, the chief of Farah province's public health department. The bombing was near a school in the city center, Bayan said. The police vehicle was slightly damaged and two officers were also wounded, said Zemeri Bashary, an interior ministry spokesman. "It is the work of enemies of Afghanistan," Bashary said, suggesting that resurgent Taliban militants were behind the attack. Western Afghanistan has been spared much of the violence rocking the south and east, but that area lays on a major heroin smuggling route into Iran. Last week, suspected Taliban militants briefly took over a district in Farah province after police fled their posts. That followed a roadside attack last Sunday on the province's police chief upon his return from destroying poppy fields. He was unharmed, but four other officers in the vehicle were killed and two wounded. Afghanistan is the world's largest opium poppy producer. In 2006, its production rose 49 percent to 6,700 tons - enough to make about 670 tons of heroin. The government has stepped up attempts to destroy poppy fields after rejecting the US idea of ground-based spraying. In southern Helmand province on Wednesday, residents discovered the body of a doctor, who was kidnapped and killed by suspected Taliban militants earlier in the week, said the province's Deputy Police Chief Gen. Mohammad Eisah. The doctor was shot in the head and chest and his body was dumped on the side of the road near Helmand's capital, Lashkar Gah, Eisah said. Also Wednesday, Afghan security forces detained 18 suspected Taliban and seized their weapons after a clash with the militants in Helmand province's Gereshk district, Bashary said.