WASHINGTON — President Barack Obama rejected the Afghanistan war options before him and asked for revisions, his defense secretary said Thursday, after the U.S. ambassador in Kabul argued that a significant U.S. troop increase would only prop up a weak, corruption-tainted government.

Obama's ambassador, Karl Eikenberry, who is also a former commander in Afghanistan, twice in the last week voiced strong dissent against sending large numbers of new forces, according to an administration official. That puts him at odds with the current war commander, Gen. Stanley McChrystal, who is seeking thousands more troops.

Eikenberry's misgivings, expressed in classified cables to Washington, highlight administration concerns that bolstering the American presence in Afghanistan could make the country more reliant on the U.S., not less. He expressed his objections just ahead of Obama's latest war meeting Wednesday.

At the war council meeting, Obama asked for changes in the four options he was given that could alter the dynamic of both how many additional troops are sent to Afghanistan and their timeline in the war zone.

Defense Secretary Robert Gates said the discussion turned on "how can we combine some of the best features of several of the options to maximum good effect." He added: "There is a little more work to do. I do think that we're getting toward the end of this process."

One issue in the discussions, Gates said, has been "How do we signal resolve and at the same time signal to the Afghans and the American people that this isn't an open-ended commitment."

The president wants to clarify how and when U.S. troops would turn over responsibility to the Afghan government, said another official, who spoke on condition of anonymity discuss administration deliberations.

Meanwhile, Richard C. Holbrooke, Obama's special representative for Afghanistan and Pakistan, left late Wednesday for consultations with allies in Berlin, Paris and Moscow. British officials also are expected at some point to join the talks, part of a continuing effort to coordinate with allies, brief them on Obama's strategy review and discuss what more they might contribute in Afghanistan.

The developments underscore U.S. skepticism about the leadership of Afghan President Hamid Karzai, whose government has been dogged by corruption. The emerging administration message is that Obama will not do anything to lock in an open-ended U.S. commitment.

U.S. Secretary of State Hillary Rodham Clinton on Thursday voiced a list of concerns about Afghanistan: "corruption, lack of transparency, poor governance, absence of the rule of law."