But he cautioned against a quick or significant U.S. withdrawal that could surrender "the gains we have fought so hard to achieve."
Gen. David Petraeus said the "horrific and indiscriminate attacks" that killed at least 250 Yazidis, an ancient religious sect, in northwestern Iraq Tuesday night were the work of al-Qaida in Iraq. That would bolster his argument, he said, against too quickly drawing down the 30,000 additional U.S. troops deployed in the first half of the year.
Petraeus said the shift in loyalty among many Sunni insurgents in Iraq's western Anbar province, Baghdad's Amariyah district and a similar hotspot in the city called Ghazaliyah was "a pretty big deal."
"You have to pinch yourself a little to make sure that is real because that is a very significant development in this kind of operation in counterinsurgency," he said. "It's all about the local people. When all the sudden the local people are on the side of the new Iraq instead of on the side of the insurgents or even al-Qaida, that's a very significant change."