SANA, Yemen — The United States, which long supported Yemen’s president, even in the face of recent widespread protests, has now quietly shifted positions and has concluded that he is unlikely to bring about the required reforms and must be eased out of office, according to American and Yemeni officials.

The Obama administration had maintained its support of President Ali Abdullah Saleh in private and refrained from directly criticizing him in public, even as his supporters fired on peaceful demonstrators, because he was considered a critical ally in fighting the Yemeni branch of Al Qaeda. This position has fueled criticism of the United States in some quarters for hypocrisy for rushing to oust a repressive autocrat in Libya but not in strategic allies like Yemen and Bahrain.

That position began to shift in the past week, administration officials said. While American officials have not publicly pressed Mr. Saleh to go, they have told allies that they now view his hold on office as untenable, and they believe he should leave.

A Yemeni official said that the American position changed when the negotiations with Mr. Saleh on the terms of his potential departure began a little over a week ago.