As the United States prepares to withdraw its troops from Iraq by year’s end, senior American and Iraqi officials are expressing growing concern that Al Qaeda’s offshoot here, which just a few years ago waged a debilitating insurgency that plunged the country into a civil war, is poised for a deadly resurgence.

Qaeda allies in North Africa, Somalia and Yemen are seeking to assert more influence after the death of Osama bin Laden and the diminished role of Al Qaeda’s remaining top leadership in Pakistan. For its part, Al Qaeda in Iraq is striving to rebound from major defeats inflicted by Iraqi tribal groups and American troops in 2007, as well as the deaths of its two leaders in 2010.

Although the organization is certainly weaker than it was at its peak five years ago and is unlikely to regain its prior strength, American and Iraqi analysts said the Qaeda franchise is shifting its tactics and strategies—like attacking Iraqi security forces in small squads—to exploit gaps left by the departing American troops and to try to reignite sectarian violence in the country.… “I cringe whenever anybody makes a pronouncement that Al Qaeda is on its last legs,” said Maj. Gen. Jeffrey Buchanan, the American military’s top spokesman in Iraq.…

The Qaeda affiliate’s nascent resurgence has helped fuel a debate between some Pentagon officials on one side, who are seeking a way to permit small numbers of American military trainers and Special Operations forces to operate in Iraq, and some White House officials on the other, who are eager to close the final chapter on a divisive eight-year war that cost the lives of more than 4,400 troops.…

According to General Buchanan, there are 800 to 1,000 people in Al Qaeda’s Iraq network, “from terrorists involved in operations to media to finance to fighters.” A document released by the military in July 2010 said Al Qaeda had about 200 “hard core” fighters in Iraq. The weak Iraqi economy is providing a large pool of young and vulnerable recruits, analysts say.… Foreigners make up only a small percentage of the organization’s membership base.…

Although the United States is withdrawing all but a handful of its remaining 33,000 troops, leaving a few to guard the American Embassy, both governments are discussing a continuing military partnership. Among the main American goals is for the Iraqi government to approve a contingent of American Special Forces that would train and assist Iraqi security forces.… The White House [has] announced that President Obama will meet with [Iraqi Prime Minister Nouri] Maliki on Dec. 12 to discuss the continuing “strategic partnership” between the United States and Iraq.…