KANDAHAR, Afghanistan (AP) — An important district in Afghanistan's southern poppy-growing province of Helmand has fallen under Taliban control after heavy fighting that killed around 17 police and wounded up to 10 others, an official said on Saturday.

The director of Helmand's provincial council, Kareem Atal, said that Taliban militants attacked a series of police checkpoints Friday night as part of a larger assault in the Kanashin district.

Earlier, his deputy, Abdul Majeed Akhonzada, told The Associated Press that Kanashin district has "fallen into Taliban hands."

The fall of the district, which borders Pakistan and major poppy-producing districts, means "Taliban are in control of 60 percent of Helmand," Akhonzada said.

Much of the area of Marjah, Sangin, Garmser and Dishu districts have already fallen to the Taliban, he said.

The district police chief and deputy head of the local branch of the national intelligence agency were critically wounded in clashes, he said.

Precise casualty figures can't be confirmed as bodies litter the ground and fighting was still underway, he added.

Atal said troops had been deployed to retake the district, but it would be a difficult task "because the Taliban have destroyed all the checkpoints."

The central authorities have been trying for many months to convince rural districts to reduce or remove police checkpoints as they are manned in small numbers by police who are vulnerable to Taliban attack.

Residents, however, prefer the checkpoints, officials have said, as they make them feel safe.

Kanashin is a major drug smuggling route. Helmand produces most of the world's opium, the raw material of heroin, which helps fund the Taliban's insurgency.

The fall of Kanashin follows a report by the Special Inspector General for Afghanistan Reconstruction concluding that government forces have lost five percent of the territory they held at the end of January.

The report released earlier this week said that about 65.6 percent of districts across Afghanistan were under government "control or influence" at the end of May, "a decrease from the 70.5 percent" at the end of January.

It said that of Afghanistan's 407 districts, 268 were under government control of influence, 36 or 8.8 percent were under insurgent control or influence, and 104 or 25.6 percent were considered "at risk."

The Taliban have been fighting to overthrow the Kabul government since 2001, when their regime was ousted by the U.S. invasion.

The insurgents consider Helmand, along with neighboring Kandahar province, to be their heartland.