WASHINGTON, Jan 31 — The United States has carried out at least a dozen operations — including commando raids and airstrikes — in the past three weeks against militants in Afghanistan aligned with the Islamic State, expanding the Obama administration’s military campaign against the terrorist group beyond Iraq and Syria.
The operations followed President Obama’s decision last month to broaden the authority of American commanders to attack the Islamic State’s new branch in Afghanistan. The administration — which has been accused by Republicans of not having a strategy to defeat the group — is revamping plans for how it fights the terrorist organization in regions where it has developed affiliates.
Many of these recent raids and strikes in Afghanistan have been in the Tora Bora region of Nangarhar Province — an inhospitable, mountainous area in the eastern part of the country, near the border with Pakistan. It was in Tora Bora that Osama bin Laden and other senior Qaeda militants took refuge during the American-led invasion in 2001, and eventually evaded capture by slipping into Pakistan.
Instructors from the American-led coalition worked with Iraqi soldiers during a live ammunition exercise last week at the Besmaya military base south of Baghdad. The emergence of Islamic State affiliates in various countries has prompted a new American approach. Credit Thaier Al-Sudani/Reuters
American commanders in Afghanistan said they believed that between 90 and 100 Islamic State militants had been killed in the recent operations. Intelligence officials estimate that there are roughly 1,000 Islamic State fighters in Nangarhar Province, and perhaps several thousand more elsewhere in the country. But even the generals leading the missions acknowledge that a resilient militant organization can recruit new fighters to replace those killed in American attacks.
“The new authority gives us the ability to take the gloves off to hold them in check, and we have been targeting them heavily and it has had quite an effect,” said Maj. Gen. Jeffrey Buchanan, the military’s deputy chief of staff for operations in Afghanistan. “But just because you take a bunch of guys off the battlefield doesn’t mean you will stop this organization.”
Although Mr. Obama had declared an end to combat missions in Iraq and Afghanistan, the operations are part of a continuing and potentially expanding American military footprint in south-central Asia, the Middle East and Africa for the fight against the Islamic State, also known as ISIS or ISIL.
In Iraq, the United States has about 3,700 troops, including trainers, advisers and commandos. There are several dozen Special Operations forces deployed in Syria. Defense Secretary Ashton B. Carter has said the United States and its allies are looking to do more, and has asked other countries — including several Arab ones — to contribute more to the military campaign as it moves to reclaim Mosul in Iraq and Raqqa in Syria, the two major cities controlled by the Islamic State.
Administration officials are weighing a new campaign plan for Libya that would deepen the United States’ military and diplomatic involvement on yet another front against the Islamic State. The United States and its allies are increasing reconnaissance flights and intelligence collecting there — and even preparing for possible airstrikes and raids, according to senior American officials. Special Operations forces have met with various Libyan groups over the past months to vet them for possible action against the Islamic State.
In Afghanistan, American and other allied commanders fear that the combination of fighters loyal to the Taliban, the Haqqani network and the Islamic State is proving too formidable for the still struggling Afghan security forces to combat on their own.
The United States has 9,800 combat troops in Afghanistan. Although that figure is scheduled to decline to 5,500 by the time Mr. Obama leaves office next January, administration and military officials are privately hinting that the president may again slow the troop withdrawal later this year.
At a hearing last week, Mr. Obama’s nominee to be the next commander in Afghanistan, Lt. Gen. John W. Nicholson Jr., was asked by Senator John McCain, chairman of the Armed Services Committee, if he believed that the overall security situation in Afghanistan was deteriorating, rather than improving.
“Sir, I agree with your assessment,” said General Nicholson, a veteran of several deployments to Afghanistan. He said that the Taliban had fought against Afghan security forces “more intensely than perhaps we anticipated” and that the emergence of the Islamic State there had been unexpected.
General Nicholson said that, if confirmed by the Senate, he would take his first 90 days to review the two primary missions in Afghanistan — counterterrorism and advising and assisting Afghan forces — before offering his recommendations on American troop levels in the country. The departing commander, Gen. John F. Campbell, is scheduled to testify before Congress this week, and he is expected to likewise underscore the rising threat from the Islamic State.
Under newly relaxed rules the White House sent to the Pentagon last month, the military now needs to show only that a proposed target is related to Islamic State fighters in Afghanistan. Before, such a target could be struck only if it had significant ties to Al Qaeda.
The military had been able to strike Islamic State targets in self-defense, but the new rules lower the standard for such offensive operations against the group.
“Suffice to say we had built up a sufficient amount of intel to be able to go after them in a robust way once we were able to take the gloves off,” General Buchanan said.
He added: “We continue to conduct operations against Al Qaeda throughout, but have been more focused on” ISIS in recent weeks.
There are significant differences between the Islamic State fighters in Afghanistan and those in Iraq and Syria.
In Afghanistan, a majority of the militants were previously part of the local Taliban or Haqqani network, and many of them have now “rebranded” themselves as members of the Islamic State. While the leaders of the group in Iraq and Syria are mostly from those countries, many of their fighters come from other Middle Eastern countries and from Europe.
The Islamic State militants in Afghanistan receive some money from leaders in Iraq and Syria, but there is little evidence that they receive much direction about when and where to launch attacks, according to military officials. There have been few examples of the Islamic State members in Afghanistan being able to effectively communicate with each other to carry out complex attacks, like the ones often carried out in Iraq and Syria. Nevertheless, the group has claimed responsibility for several deadly bombings in Afghanistan in recent months.
President Ashraf Ghani of Afghanistan has thanked American officials for their recent efforts against the Islamic State, which he fears is gaining strength, according to senior American officials.
As the Islamic State has expanded in Afghanistan, it has also fought the Taliban as the two groups compete for influence and money.
“They are trying to assume control at the local level over checkpoints, over the drug trade, over flows of illicit goods,” Brig. Gen. Wilson A. Shoffner, a spokesman for the American military in Afghanistan, said in a telephone interview on Sunday.