Gen. David Petraeus, who commands U.S. forces in the Middle East, said he does not expect progress in Afghanistan to mirror the quick and dramatic results achieved under the troop surge in Iraq in 2007.
Petraeus, who commanded U.S. forces in Iraq in 2007, said the Afghanistan plan will focus on selected regions and proceed in phases.
"This will be a step-by-step operational campaign," Petraeus told USA TODAY. "There will at times be increases in violence, undoubtedly, as the Taliban fight back to try to hang on to a particular safe haven and sanctuary."
Petraeus led the largely successful surge in Iraq, where a change in tactics backed by an influx of about 30,000 additional U.S. servicemembers seized the initiative from insurgents.
In Iraq, there was an initial spike in violence in early 2007, but by the time Petraeus returned to Washington that September to testify to Congress, he could point to dramatic progress.
Unlike in Iraq, Afghanistan has a rural insurgency in which militants are holed up in isolated regions that are hard to get to and have little contact with neighboring valleys.
"We do have to be measured in our expectations," said Petraeus, who heads Central Command, which is based in Tampa.
Petraeus pointed out that the quick progress in Iraq is easier to see when looking back.
"It didn't seem rapid if you were watching it on the ground, and particularly if you were looking ahead and realizing that (in) September 2007 you were going to have to testify," the general said.
In Afghanistan, U.S. forces have already launched counterinsurgency campaigns in key areas. For example, an influx of U.S. Marines this year secured much of the Helmand River Valley.
The Marines' ability to secure the region while working with Afghan security forces is being viewed as a success by the Pentagon.
"I think one of the reasons that our military leaders are pretty confident is that they have already begun to see changes where ... the Marines are present in southern Helmand," Defense Secretary Robert Gates told ABC's This Week With George Stephanopoulos.
U.S. commanders also have announced plans to support tribes and villages that want to defend themselves against the Taliban and other insurgents.
The plan, called the Community Defense Initiative, bears some resemblance to a key development in Iraq's western Anbar province in 2006, when tribes turned on al-Qaeda. The movement quickly spread.
In Afghanistan, Petraeus said, U.S. commanders will be examining different regions separately in an effort to determine which tactics are working.
"There are a few of those beginning to emerge, certain areas that are becoming canaries in the mineshaft," Petraeus said.
"If you aggregate it too much, you might miss a sense of the fact that a certain approach is working in a certain place and one that might be replicated somewhere else," he said.
President Obama's plan, unveiled last week, calls for sending 30,000 U.S. reinforcements to Afghanistan, bringing the total of U.S. servicemembers there to about 100,000.
The White House said the strategy would be assessed in December 2010 and the process of turning security responsibility over to Afghan forces would begin in July 2011.
White House officials, however, have said the pace of the U.S. withdrawal would be based on conditions.
"What is conditions-based is the pacing at which our troops will come home and the pace at which we will turn over responsibility to the Afghans," Gates told CBS' Face the Nation on Sunday. "That will be based on conditions on the ground."
Gates said there will probably be a significant U.S. military presence in Afghanistan for two to four more years.