Having been repeatedly rebuffed, the Americans tried Thursday to use the best lever they have: they cut off all American financing to Pul-e-Charki until they can confirm that the invasive searches have stopped, two Western officials said. The United States has spent about $14.2 million on improvements at the prison since June 2009.

But with no word yet on what impact the latest American move has had, Western officials and rights advocates here are viewing the hard line as a troubling sign: not just of waning Western influence as relations have worsened, but also for maintaining hard-won gains in rights for women in Afghanistan as the prospect of a speeded-up American withdrawal has become a greater possibility.

This is not an oversimplified case of high-minded Westerners versus conservative Afghans. The West’s role in Afghanistan has empowered many Afghans to champion women’s and minority rights in the past decade, and those home-grown reformers have helped establish most of the social changes that have been seen as encouraging steps here.

Yet the Afghans at the forefront of pressing for those rights are already finding themselves increasingly marginalized as Afghanistan’s old guard flexes its muscles. In fact, the official in charge of all of Afghanistan’s civilian prisons, Gen. Amir Jamshid, has tried and failed to stop the invasive searches of women, his objections overridden by Mr. Mohammadi, the interior minister, Afghan and American officials said. Those officials spoke on condition of anonymity to avoid offending their Afghan counterparts.

Other worrying signs have appeared. President Hamid Karzai in December removed outspoken members of the Afghanistan Independent Human Rights Commission, which is appointed by the government but acts independently.