WASHINGTON -- President Barack Obama is confronting a split among his closest advisers on Afghanistan, reflecting divisions in his own party over whether to send in thousands more U.S. troops and complicating his efforts to adopt a war policy he can sell to a public grown weary of the 8-year-old conflict.

With top military commanders and congressional Republicans pushing for a troop increase, Obama pressed key members of his national security team Wednesday for their views during an intense, three-hour session in a packed White House Situation Room.

According to The Wall Street Journal, the discussion focused on the political and security situation on the ground, according to an administration official, with military commanders detailing the gains made by the insurgency and top diplomats discussing the Afghan election results that were marred by fraud claims.

In an interview with the Journal, a senior defense official said that Defense Secretary Robert Gates now worries that counterinsurgency might no longer be a viable approach for countering the Taliban violence roiling once-stable parts of north and west Afghanistan.

Gates, a Bush administration holdover, has emerged as one of Obama's most trusted advisers, so his views carry significant weight in the deliberations.

"Even 40,000 more troops don't give you enough boots on the ground to protect the Afghans if the north and west continue to deteriorate," the official said. "That may argue for a different approach."

A shift in Gates's thinking would be particularly striking because he has long been a major advocate of counterinsurgency, which is credited with helping to sharply reduce Iraq's once-unrelenting violence.

The meeting didn't include specific discussions of troop levels, a senior administration official said. At its conclusion, Obama reminded the crowd that he hadn't reached a decision and that his war council should return twice next week with more details and ideas, the official said. The official spoke on condition of anonymity to discuss the private deliberations.

The talks revealed the emerging fault lines within the administration, with military commanders solidly behind the request for additional troops and other key officials divided.

Secretary of State Hillary Rodham Clinton and special Afghan and Pakistan envoy Richard Holbrooke appeared to be leaning toward supporting a troop increase, the official said.

White House chief of staff Rahm Emanuel and Gen. James Jones, Obama's national security adviser, appeared to be less supportive, the official said. Vice President Joe Biden, who attended the meeting, has been reluctant to support a troop increase, favoring a strategy that directly targets Al Qaeda fighters who are believed to be hiding in Pakistan.

The meeting, the second of at least five Obama has planned as he reviews his Afghanistan strategy, comes after a critical assessment of the war effort from Gen. Stanley McChrystal, the man he put in charge of the war earlier this year. McChrystal declared that the U.S. would fail to meet its objectives of causing irreparable damage to Taliban militants and their Al Qaeda allies if the administration did not significantly increase American forces.

McChrystal is widely believed to want to add between 30,000 and 40,000 to the current U.S. force of 68,000.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, and Gen. David Petraeus, the top commander for the wars in Iraq and Afghanistan, both support McChrystal's strategy, Pentagon press secretary Geoff Morrell said. Gates is on the fence, the spokesman said.

White House officials say it may take weeks more before the president decides whether to overhaul the U.S. strategy in Afghanistan or send more troops.

Jones told senators in a classified briefing after the White House meeting that the administration's evolving Afghanistan strategy depends in large part on the outcome of the disputed Afghan election. Those decisions are expected in a matter of weeks.

"It's not just the election but the reaction to the election that we'll be watching for," said Sen. Jack Reed, a Democrat from Rhode Island.

As Obama deliberates, key Democrats in Congress have begun voicing concern about the U.S.-led effort in Afghanistan, questioning whether a further commitment of blood and treasure is wise or necessary. The most vocal support for continuing or even expanding the conflict comes from Republicans.

Support for the war has fallen off sharply among Americans, with just more than half now saying the conflict is not worth the fight.

The Wall Street Journal's Yochi Dreazen contributed to this report.