KABUL — The labs themselves are simple, tucked into nondescript huts or caves: a couple of dozen empty barrels for mixing, sacks or gallon jugs of precursor chemicals, piles of firewood, a press machine, a generator, and a water pump with a long hose to draw from a well dug nearby.

They are heroin refining operations, and the Afghan police and US Special Forces keep running into them all over Afghanistan this year. Officials and diplomats are increasingly worried that the labs’ proliferation is one of the most troubling turns yet in the long struggle to end the Taliban insurgency.

That the country has consistently produced about 85 percent of the world’s opium, despite more than $8 billion spent by the United States alone to fight it over the years, is accepted with a sense of helplessness among counternarcotics officials.

For years, most of the harvest would be smuggled out in the form of bulky opium syrup that was refined in other countries. But now, Afghan and Western officials estimate that half, if not more, of Afghan opium is getting some level of processing in the country, either into morphine or heroin with varying degrees of purity.

The refining makes the drug much easier to smuggle out into the supply lines to the West. And it is vastly increasing the profits for the Taliban, for whom the drug trade makes up at least 60 percent of their income, according to Afghan and Western officials.

“Without drugs, this war would have been long over,’’ President Ashraf Ghani of Afghanistan said recently. “The heroin is a very important driver of this war.’’

Zabiullah Mujahid, a Taliban spokesman, said the group “had nothing to do’’ with processing heroin, and denied that major laboratories existed in the areas under its control.

The Taliban have long profited from the opium trade by taxing and providing security for producers and smugglers.

But increasingly, the insurgents are directly getting into every stage of the drug business themselves, rivaling some of the major cartels in the region — and in some places becoming indistinguishable from them.

The opium economy in Afghanistan grew to about $3 billion in 2016, almost doubling the previous year’s total and amounting to about 16 percent of the country’s gross domestic product, according to the UN Office on Drugs and Crime.

The increase in processing means the Taliban have been able to take a greater share of the $60 billion that the global trade in the Afghan opium crop is estimated to be worth. Demand remains high in Europe and North America: Ninety percent of the heroin on the streets of Canada, and about 85 percent in Britain, can be traced to Afghanistan, the State Department says.

Despite the size of Afghanistan’s opium problem, not much is being done about it. Opium eradication or interception got little attention in the Trump administration’s new strategy for the Afghan war.

Various police forces bear the brunt of the drug war in Afghanistan, but are often complicit in the opium trade themselves.

The fight to disrupt the flow of Afghan drugs to Western and regional capitals, and cash to the coffers of the Taliban, has largely fallen on a small police unit, the National Interdiction Unit, of about 450 to 600 commandos who are mentored by US Special Forces.

“We have to merge these two things together: the counterterrorism and the counternarcotics. It has to go hand in hand, because if you destroy one, it is going to destroy the other,’’ said Javid Qaem, the Afghan deputy minister of counternarcotics.