WASHINGTON — Gen. David H. Petraeus, the top American commander in Afghanistan, said Thursday that President Obama’s new schedule for drawing down forces there was “more aggressive” than he had recommended and increased the risk that the military would not meet all its goals.

But General Petraeus, pressed for his personal views at a Senate hearing on his nomination as director of central intelligence, said the president had to consider many factors beyond the battlefield and that he fully accepted Mr. Obama’s plan. It would bring home 33,000 troops by September 2012 and withdraw the remaining 68,000 by the end of 2014.

“There are broader considerations beyond those just of a military commander,” General Petraeus told the Senate Intelligence Committee. “The commander in chief has decided, and it is then the responsibility, needless to say, of those in uniform to salute smartly and to do everything humanly possible to execute it.”

He said he had received some e-mails suggesting that he resign if he disagreed with the president’s decision, which would require troops to depart before the end of next year’s fighting season. “I’m not a quitter,” he said, noting that the troops under his command do not have the option of walking off the job, and that a general should take such a step only in a “dire” situation.