"I'm not considering it at that point because I haven't received the request," the president said during a taped interview for "Face the Nation" Friday.
CBS News Pentagon correspondent David Martin reported that the request was imminent.
Mr. Obama said that when he took office he ordered a comprehensive review of the situation in Afghanistan, which was "adrift" after the Bush administration.
"In the meantime," he said, "I sent 21,000 troops to make sure that we could secure the election," held in August.
"[M]y job is to make sure that we get a strategy that focuses on my core goal which is to dismantle and destroy al Qaeda and its allies that killed Americans and are still plotting to kill Americans," he insisted.
More from "Face the Nation" (9/20/09):
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Full Transcript: Obama on 'Face the Nation'
Schieffer asked for the admission that it would be difficult for the president to deny the general's potential request for more troops.
"The only reason I send a single young man or woman in uniform anywhere in the world is because I think it is necessary to keep us safe," he replied.
"Didn't you say on March 27th that you have announced a comprehensive new strategy for Afghanistan?" Schieffer asked. "I thought you already had a strategy."
"We did," the president explained, "but what I also said was that we were going to review that review that every six months."
Any additional troops sent to Afghanistan would be the result of one of these reviews which concluded that more troops would help, he explained.