WASHINGTON — Even as the Obama administration scrambles to confront the Islamic State and resurgent Taliban, an old enemy seems to be reappearing in Afghanistan: Al Qaeda training camps are sprouting up there.
That is forcing the Pentagon and US intelligence agencies to assess whether they could again become a breeding ground for attacks on the United States.
Most of the handful of camps are not as big as those that Osama bin Laden built before the Sept. 11, 2001, attacks. But had they reemerged several years ago, they would have rocketed to the top of potential threats presented to President Obama in his daily intelligence briefing.
Now, they are just one of many — and perhaps, US officials say, not even the most urgent on the Pentagon's list in Afghanistan.
The scope of Al Qaeda's deadly resilience in Afghanistan appears to have caught US and Afghan officials by surprise. Until this fall, US officials had largely focused on targeting the last remaining senior Qaeda leaders hiding along Afghanistan's rugged, mountainous border with Pakistan.
At least in public, the administration has said little about the new challenge or its strategy for confronting the threat from Al Qaeda, even as it rushes to help the Afghan government confront what has been viewed as the more imminent threat, the surge in violent attacks from the Taliban, the Haqqani network and a new offshoot of the Islamic State.
Former administration officials have been more outspoken — especially those who were on the front lines of the original battle to destroy Al Qaeda's central leadership.
"I do worry about the rebirth of AQ in Afghanistan because of what their target list will be — us," said Michael Morell, the deputy director of the CIA until two years ago, whose book, "The Great War of Our Time," recounts the efforts of the Bush and Obama administrations to destroy the Qaeda leadership.
"It is why we need to worry about the resurgence of the Taliban," Morell said, "because, just like before, the Taliban will give Al Qaeda a safe haven."
A senior administration official offered a different view, saying that the increased Qaeda activity was more the result of Pakistani military operations pushing fighters across the border into Afghanistan than al-Qaeda enlisting new Afghan recruits inside the country.
In October, US and Afghan commandos, backed by scores of US airstrikes, attacked a Qaeda training camp in the southern part of the country that military officials said was one of the largest ever discovered.
The assault, which took place over several days, pounded two training areas — one sprawled over 30 square miles — that featured elaborate tunnels and fortifications. As many as 200 fighters were killed, US officials said.
Senior administration officials concede that there are other Qaeda camps or bases, including at least one in Helmand province, though they are not certain exactly how many because they were made harder to detect after the October assault.
The two camps attacked in the fall were in a sparsely populated area of Kandahar province along Afghanistan's southern border with Pakistan.
Some of the facilities apparently were in place for up to a year and a half, undetected by US or Afghan spies or surveillance aircraft.
General John F. Campbell, the top US commander in Kandahar, has been sounding a warning about Al Qaeda, in the broader context of Afghanistan's complex threat environment, telling Congress in October that Afghan security forces "have thus far proven unable to eradicate Al Qaeda entirely."
"Al Qaeda has attempted to rebuild its support networks and planning capabilities with the intention of reconstituting its strike capabilities against the US homeland and Western interests," Campbell said.