WASHINGTON -- After months of deliberating, President Obama opted not to accept any of the Afghanistan war options presented by his national security team, pushing instead for revisions to clarify how and when U.S. troops would turn over responsibility to the Afghan government, a senior administration official said Wednesday.

That stance comes in the midst of forceful reservations about a possible troop buildup from the U.S. ambassador in Afghanistan, Karl Eikenberry, according to a second top administration official.

In strongly worded classified cables to Washington, Eikenberry said he had misgivings about sending in new troops while there are still so many questions about the leadership of Afghan President Hamid Karzai.

Eikenberry, who once commanded forces in Afghanistan, resigned his Army commission to take the job as U.S. ambassador in Kabul earlier this year, and his is an influential voice among those advising President Barack Obama on Afghanistan.

Eikenberry sent multiple classified cables to Washington over the past week that question the wisdom of adding forces when the Afghan political situation is unstable and uncertain, said an official familiar with the cables. The official spoke on condition of anonymity to discuss internal administration deliberations and the classified documents.

Cables are diplomatic messages that may or may not be classified and carry greater heft than other forms of communication such as e-mail.

Eikenberry made the point that the administration should step cautiously in planning for any troop buildup while there are still so many questions surrounding Afghan President Hamid Karzai, the official said. Eikenberry is the front line U.S. official dealing with Karzai, the U.S.-backed leader whose administration was stained by corruption and mismanagement. It was a visiting senior senator, Democrat John Kerry of Massachusetts, who was instrumental in persuading Karzai last month to accept the findings of a U.N. panel that his re-election vote in August was too marred by fraud to stand.

Karzai agreed to a second round of voting but was elevated to a second term as president without a runoff election when his challenger dropped out. Since then, U.S. officials have been alarmed at some of Karzai's remarks and the lack, so far, of meaningful steps to clean house.

Eikenberry's objections were a wild card in the midst of what had appeared to be the final days of Obama's long decision-making process on how to revamp U.S. strategy in the 8-year war. Eikenberry has participated in some of Obama's war council sessions over the past several weeks.

Military officials said Obama has asked for a rewrite before and resisted what one official called a one-way highway toward war commander Gen. Stanley McChrystal's recommendations for more troops. The sense that he was being rushed and railroaded has stiffened Obama's resolve to seek information and options beyond military planning, officials said, though a substantial troop increase is still likely.

The president was considering options that include adding 30,000 or more U.S. forces to take on the Taliban in key areas of Afghanistan and to buy time for the Afghan government's small and ill-equipped fighting forces to take over. The other three options on the table Wednesday were ranges of troop increases, from a relatively small addition of forces to the roughly 40,000 that the top U.S. general in Afghanistan prefers, according to military and other officials.

The key sticking points appear to be timelines and mounting questions about the credibility of the Afghan government.

Administration officials said Wednesday that Obama wants to make it clear that the U.S. commitment in Afghanistan is not open-ended. The war is now in its ninth year and is claiming U.S. lives at a record pace as military leaders say the Taliban has the upper hand in many parts of the country.

Eikenberry, the top U.S. envoy to Kabul, is a prominent voice among those advising Obama, and his sharp dissent is sure to affect the equation. He retired from the Army this year to become one of the few generals in American history to switch directly from soldier to diplomat, and he himself is a recent, former commander of U.S. troops in Afghanistan.

Eikenberry's cables raise deep concern about the viability of the Karzai government, according to a senior U.S. official familiar with them who spoke on condition of anonymity to discuss the classified documents. Other administration officials raised the same misgivings in describing Obama's hesitancy to accept any of the options before him in their current form.

The options presented to Obama by his war council will now be amended.

Military officials say one approach is a compromise battle plan that would add 30,000 or more U.S. forces atop a record 68,000 in the country now. They described it as "half and half," meaning half fighting and half training and holding ground so the Afghans can regroup.

The White House says Obama has not made a final choice, though military and other officials have said he appears near to approving a slightly smaller increase than McChrystal wants at the outset.

Among the options for Obama would be ways to phase in additional troops, perhaps eventually equaling McChrystal's full request, based on security or other conditions in Afghanistan and in response to pending decisions on troops levels by some U.S. allies fighting in Afghanistan.

The White House has chafed under criticism from Republicans and some outside critics that Obama is dragging his feet to make a decision.

Obama's top military advisers have said they are comfortable with the pace of the process, and senior military officials have pointed out that the president still has time since no additional forces could begin flowing into Afghanistan until early next year.

Under the scenario featuring about 30,000 more troops, that number most likely would be assembled from three Army brigades and a Marine Corps contingent, plus a new headquarters operation that would be staffed by 7,000 or more troops, a senior military official said. There would be a heavy emphasis on the training of Afghan forces, and the reinforcements Obama sends could include thousands of U.S. military trainers.

Another official stressed that Obama is considering a range of possibilities for the military expansion and that his eventual decision will cover changes in U.S. approach beyond the addition of troops. The stepped-up training and partnership operation with Afghan forces would be part of that effort, the official said, although expansion of a better-trained Afghan force long has been part of the U.S objective and the key to an eventual U.S. and allied exit from the country.

With the Taliban-led insurgency expanding in size and ability, U.S. military strategy already has shifted to focus on heading off the fighters and protecting Afghan civilians. The evolving U.S. policy, already remapped early in Obama's tenure, increasingly acknowledges that the insurgency can be blunted but not defeated outright by force.