The top American commander in Iraq said Wednesday he was preparing recommendations on troop cuts before he returns to Washington next month for a report to Congress and understands the US footprint in Iraq will have to be "a good bit smaller" by next summer. But he cautioned against a quick or significant US withdrawal that could surrender "the gains we have fought so hard to achieve." 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. The general issued his comments to a small group of reporters who accompanied him to the headquarters of a group of former Sunni insurgents who are now working with American and Iraqi forces against al-Qaida in western Baghdad's Amariyah neighborhood.