"I think we have reason to believe -- and I think our forces have been alerted to the possibility -- that we will likely see an uptick in violence leading up to the June 30 deadline for U.S. combat forces to leave Iraqi cities and towns," Morrell told Pentagon reporters.
He cited past patterns in which terrorists and insurgents increased their attacks in the days leading up to elections and other significant milestones.
Recent incidents in Iraq, including the "horrific" bombing south of Kirkuk last weekend, also indicate a possible repeat before U.S. combat troops leave urban areas in accordance with the U.S.-Iraqi status of forces agreement, Morrell said.
Army Gen. Raymond T. Odierno, commander of Multinational Force Iraq, has expressed confidence in the capabilities of both his forces and the Iraqi security forces to deal with the increased threat level, Morrell said. As combat troops leave the cities, they'll form "layers of defense" outside the urban areas and continue to conduct combat operations with Iraqi security forces.
However, smaller contingents of U.S. troops will remain behind to support the Iraqi security forces until they're no longer needed. "This is going to be a coordinate/train/advise/assist role," he said. "So we'll really be there as a complement to them."
Morrell cited progress in improving security in Iraq and helping the Iraqi security forces develop capacity.
"Security incidents, despite that awful attack, remain at all-time lows since March of 2003," he said. "So despite the fact that you've seen sporadic high-profile attacks still taking place in Iraq, the overall security climate is a good one."
Morrell stopped short of declaring victory over the insurgency. "We think we have beaten back al-Qaida to the point where they are now conducting attacks that are basically propaganda campaigns in an attempt to make it look as though they are driving us out of the Iraqi cities," he said. "In fact, the truth of the matter is that ... the work of our brave men and women in uniform over the past couple years has created a climate such that we can leave Iraqi cities, and the Iraqi security forces are developed to the point where they are capable of taking over that responsibility."
Meanwhile, progress has continued on the economic and political fronts as well.
"All those things are improvements," Morrell said. "And we signed a security agreement with the Iraqis nearly a year ago in which they asked us to stay in Iraq for the next three years to help them continue to build upon that momentum.
"We view that obligation seriously, and we intend to honor it," he added.