WASHINGTON – President Obama is expected to unveil his U.S. troop reduction plan for Afghanistan next week, buoyed by assessments by senior Defense Department officials that the U.S. war strategy is headed in the right direction and has weakened the Taliban-led insurgency.

But some U.S. officials in Washington and in Afghanistan are concerned that many of the gains aren’t sustainable, and conditions are too fragile to allow for the “significant” troop drawdown Obama is being pressured to begin next month by some top aides and growing numbers of lawmakers of both parties.

Violence is worse, many Taliban appear to have moved elsewhere rather than fight U.S. forces surged into the south, the Afghan government and security forces remain far from capable, and counterinsurgency cooperation with Pakistan is all but frozen, these U.S. officials said.

“The situation is terrible. Has there been a qualitative change that disadvantages the opposition and advantages the (U.S.-led) coalition? I don’t buy it,” said a U.S. official who requested anonymity because he wasn’t authorized to speak publicly. “The Taliban remains a clever, adaptive enemy.”

Moreover, there has been no apparent progress toward convening talks on a political settlement with the Taliban following three secret meetings between a senior U.S. diplomat and a former top aide to Mullah Mohammad Omar, the Taliban leader based in southwestern Pakistan.

While the U.S. surge has dealt the insurgents major setbacks and Osama bin Laden is dead, Omar and other hard-liners have few incentives to negotiate given the growing domestic pressure on Obama to begin withdrawing U.S. troops and meet a 2014 deadline for all combat forces to be out, some experts said.

“We have to display steadfastness, cohesion and purpose, and I think all of those things are in doubt about us,” said Ronald Neumann, the U.S. ambassador to Kabul from 2004 to 2007.

Army Gen. David Petraeus, the commander of U.S.-led forces in Afghanistan, submitted his drawdown options this week to the White House, where they are so tightly held that administration spokesmen refused to confirm when Obama would announce his final decision.

Petraeus’ proposal includes a recommendation to shift U.S. surge troops out of parts of southern Kandahar and Helmand provinces to eastern provinces bordering Pakistan, where the Taliban and allied groups maintain sanctuaries, according to several U.S. officials who requested anonymity.

Afghan army and police units, accompanied by U.S. military mentors, would replace the U.S. forces redeployed from Kandahar’s Arghandab Valley and the Helmand River Valley, they said.

Obama pledged to begin withdrawing some of the 100,000 U.S. troops next month in a Dec. 1, 2009, speech in which he laid out his strategy to prevent a Taliban takeover of Afghanistan that would allow al-Qaida to re-establish a sanctuary in the war-ravaged country of 36 million.

The president is under considerable pressure to pull out a significant portion of the 30,000 additional soldiers he ordered there for a surge, from members of both parties eager to reduce federal spending and from a majority of Americans weary of the nearly decade-old war.

The killing of bin Laden in a May 2 U.S. Navy SEAL raid on his hideout near Pakistan’s capital, Islamabad, has added to that pressure.

Some Obama lieutenants, led by Vice President Joe Biden, also are reportedly pushing for a substantial reduction, their eyes on Obama’s campaign for re-election next year.

Senior Pentagon officials insist that the U.S. strategy — coupling military operations with training 305,000 Afghan security forces by October, and intensified efforts to improve governance, build infrastructure and boost government services — is headed in the right direction.

They point to a weakened Taliban presence and revived commerce and development in southern areas that the militants once dominated, the expanding Afghan army and police, and Pakistan’s deployment of 140,000 troops on the border to block insurgents from crossing.

The Afghan government is due to assume security next month in seven provinces and districts in a process that is due to culminate in its assumption of security nationwide by 2014.

Many Afghans want the Americans to leave, even though they have little faith that their forces can prevail, U.S. commanders say.

At least 32 coalition troops have been killed this month. Last June, 103 troops died, the deadliest month of the war.