The U.S. and Afghanistan launched a series of strikes on Nov. 19 targeting alleged narcotics laboratories, a key source of revenue for the Taliban. (U.S. Air Forces Central Command Public Affairs/DVIDS)

U.S. and Afghan forces have launched a series of attacks on narcotics laboratories in southern Afghanistan, marking the start of what could become a long, expanded air war there under President Trump.

The initial strikes, which began Sunday and were ongoing Monday, represent the first significant use of new legal authorities granted by the Trump administration in August that enable the Pentagon to target Taliban revenue streams, said Army Gen. John W. Nicholson Jr., the top U.S. commander in Afghanistan. Previously, the U.S. military conducted strikes only when facing imminent threat or working directly with the Afghans.

Speaking to the Pentagon press corps via satellite from his headquarters in Kabul, Nicholson said Monday that Afghan A-29 warplanes launched the operation. They were followed by B-52 bombers, advanced F-22 fighters, unmanned aircraft and Marine Corps rocket fire.

“There are many, many targets that have been identified,” Nicholson said. “We are striking some, and we will continue to strike these targets as we further refine them.”

Asked why the strikes were not carried out until now, nearly three months after Trump approved his new strategy, Nicholson said the operation required extensive preparation and observation by surveillance aircraft. The Drug Enforcement Administration estimates there are 400 to 500 opium laboratories across Afghanistan, he said, and about 10 of them have been bombed so far.

“These strikes required the mapping of their revenue streams, and mapping of their infrastructure in areas where we had not done this before,” Nicholson said.

Hundreds of intelligence analysts have been involved, along with hundreds of hours of aerial surveillance, he added. He indicated that the tempo of airstrikes in coming days will be roughly the same.

The strikes have been concentrated in northern Helmand province, an area where the Taliban have long held sway. More than 20,000 Marines were based there during the Obama administration, rooting out the Taliban while training Afghan forces to fight the militants. The Taliban swiftly reclaimed large swaths of territory after the Marines withdrew in 2014.

The strikes Sunday hit seven Taliban drug laboratories and a headquarters in three districts across northern Helmand. Three occurred in Kajaki district, four in Musa Qala and one in Sangin — all areas controlled by the U.S. military at the height of Obama’s troop surge there. The largest, carried out by a B-52, struck a opium-processing facility where 50 barrels of drugs were cooking at the time, Nicholson said. Video released by the Pentagon shows the building being consumed by a massive fireball.

The U.S. government has pursued various anti-drug strategies during its 16-year war in Afghanistan, but it has done little to hamper the steady resurgence of opium poppy cultivation and drug trafficking since the Taliban’s fall in 2001. While in power before the U.S. invasion, the Taliban banned poppy growing as un-Islamic and staged bonfires of confiscated opium and heroin.

Until now, though, those U.S. efforts have only occasionally involved the military. During the early post-Taliban years, the Pentagon focused exclusively on pursuing al-Qaeda and Taliban insurgents and expressly avoided diverting efforts toward curbing the drug trade. In some cases, this was because of U.S. alliances with warlords or regional strongmen who were involved in drugs.

Later, as both poppy production and drug trading rebounded, the U.S. launched several ambitious programs to counter them. One was a crop substitution campaign that encouraged and paid farmers to grow almonds, apricots, green vegetables and saffron instead of poppy. Another paid farmers cash to destroy their poppy fields and funded interdiction campaigns in which Afghan security forces burned fields under cultivation.

These efforts were fatally hampered by a mix of factors, including the enormous appeal of drug profits, the long-accepted tradition of poppy growing by small farmers, the involvement of powerful Afghans in the trade, local hostility to interdiction, and the hardiness that enabled poppy plants to thrive in harsh and dry conditions.

Meanwhile, the Taliban insurgents, apparently abandoning their previous religious scruples, became increasingly involved in both poppy cultivation and drug trafficking as a means of supporting the war, especially in Helmand province. At first they primarily demanded taxes from growers, but gradually the overlap between Taliban recruits and local agricultural labor became so pronounced that the insurgents essentially suspended military operations during poppy harvest seasons.

Nicholson said that the new strategy does not focus on regular Afghans who farm poppy. Rather, it will target Taliban drug processing hubs, with the hope that if the Afghan government can expand the area it controls, it can encourage the growth of other legal crops.

Afghan President Ashraf Ghani expressed support for the new bombing campaign. The U.S. and Afghan governments are determined to tackle his country’s “criminal economy and narcotics trafficking with full force,” he said on Twitter.

The strikes are not expected to have a a significant effect on the supply of U.S. heroin or other illegal opium-based products, the majority of which comes Mexico. Nicholson said that about 4 percent of heroin in the United States comes from Afghanistan.

The aircraft involved came from U.S. bases inside and outside Afghanistan — a reflection, in part, of how much the air campaign against the Islamic State in Iraq and Syria has slowed. The F-22, which cost about $340 million each to make, was used for the first time ever in Afghanistan on Sunday. Nicholson said it was chosen because of its ability to carry precise, 250-pound small-diameter bombs, though other U.S. aircraft also carry those weapons. The jet also has advanced sensors and is sometimes used at the top of a “stack” of strike aircraft to oversee the airspace.

U.S. airstrikes are up significantly in Afghanistan since Trump announced his new strategy in August. The Air Force alone dropped 503 weapons in August and 414 in September, up from 108 and 162 during the same months last year, according to statistics released by the service. The Air Force had dropped 2,901 weapons in Afghanistan in 2017 through the end of September, up from 1,337 in all of 2016 and 947 in all of 2015.

This story has been updated to clarify the past relationship between the U.S. military and drug interdiction efforts in Afghanistan.

Pamela Constable contributed to this report from Kabul.