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…

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 and some reporters that they now view his hold on office as untenable, and they believe he should leave…

One administration official referred to that concern last week, saying that the standoff between the president and the protesters “has had a direct adverse impact on the security situation throughout the country.”

“Groups of various stripes — Al Qaeda, Houthis, tribal elements, and secessionists — are exploiting the current political turbulence and emerging fissures within the military and security services for their own gain,” the official said. “Until President Saleh is able to resolve the current political impasse by announcing how and when he will follow through on his earlier commitment to take tangible steps to meet opposition demands, the security situation in Yemen is at risk of further deterioration.”