KABUL, Afghanistan - A roadside bomb in western Afghanistan left three civilians dead and 48 wounded, including 10 children, officials said Thursday.

The blast targeted a passing police vehicle in the city of Farah, said Mohammad Qasem Bayan, the chief of public health department for Farah province.

The attack happened in the city center near a school, Bayan said.

The police vehicle was slightly damaged and two officers also were wounded, said Zemeri Bashary, a spokesman for the ministry of interior.

"It is the work of enemies of Afghanistan," Bashary said, suggesting the resurgent Taliban militants were behind the attack.

Western Afghanistan has been spared much of the violence rocking the country's south and east, but that area is on a major route for heroin smuggling into Iran.

Last week, suspected Taliban militants briefly took over one of the districts of Farah province after police fled the posts.

That followed a roadside attack last Sunday on the province's police chief on his return from destroying poppy fields. The police chief was unharmed, but four other officers in the vehicle were killed and two wounded.

Afghanistan is the world's largest producer of opium poppy. In 2006, production in the country rose 49 percent to 6,700 tons -- enough to make about 670 tons of heroin.

The government has stepped up its attempts to destroy poppy fields after rejecting the U.S. idea of ground-based spraying of the illicit crop.

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 Gen. Mohammad Eisah, the province's deputy police chief.