The Bush administration is considering the withdrawal of additional combat forces from Iraq beginning in September, according to administration and military officials, raising the prospect of a far more ambitious plan than expected only months ago.

Gen. David H. Petraeus signaled one adjustment in recent testimony to Congress, saying that he would probably recommend troop reductions in the fall going beyond the ongoing pullback of the five "surge" brigades deployed last year.

Gen. Petraeus pointed out that attacks in Iraq hit a four-year low in mid-May and that Iraqi forces were finally taking the lead in combat and on multiple fronts at once — something that was inconceivable a year ago. As a result the Iraqi government of Nouri al-Maliki now has "unparalleled" public support, as Gen. Petraeus put it, and U.S. casualties are dropping sharply.