Washington ? Chinese President Jiang Zemin is not passing quietly into retirement as once expected, having launched a surprise bid to retain authority over his presumed successor, Hu Jintao, U.S. officials say.

Jiang’s attempt to retain power could forestall the passing of China’s current generation of leaders, assuming his contemporaries, all 70 and older, would elect to stay on as well, said the officials, speaking to The Associated Press on condition of anonymity.

Hu, the current vice president, isn’t ready to roll over in the face of Jiang’s desire to stay, either.

And with no single person or group powerful enough to determine whether Jiang stays or goes, the U.S. government is left wondering who will be leading the world’s most populous nation after next spring, the officials said.

From the American standpoint, few overt differences exist in the policies of the two, although U.S. officials say the bland Hu has made little known about himself.

The Bush administration has not indicated whom it prefers, but some U.S. officials favor Hu over Jiang, simply because he is seen as a step closer to China’s younger generations, who they feel are more amenable to negotiation on a variety of matters.

The succession question is expected to be settled in the fall at the meeting of China’s 16th Communist Party Congress. The meeting had been expected in September but might be delayed until after late October when Jiang visits the United States and Mexico. Selected leaders would be expected to take their new state positions the following March.

Jiang’s campaign to stay put is thought to have begun in February. State-controlled media now highlight articles about Jiang and his communist philosophy.

In April and May, Hu visited the United States and was widely viewed as China’s next leader. Hu is a decade younger and leads China’s “fourth generation” of leaders. Mao Zedong, Deng Xiaoping and Jiang led the first three. Mao’s communist supporters won power in 1949 when nationalist leaders fled to Taiwan.

Jiang had been expected to retire from the presidency this year under an informal age limit of 70 set in 1977 for members of the ruling Politboro. Several other leaders also were expected to step down.

Jiang was to have stayed as political leader of China’s military, while Hu was to have become president of China and general secretary of the Chinese Communist Party.

American analysts envision a number of possible outcomes:

No real changes. Jiang remains president, and Hu continues to wait as vice president. Hard-line legislative chief Li Peng and Premier Zhu Rongji might retain their positions.

Jiang could be forced to retire from the presidency and maintain only his military leadership position. Hu would become the real leader.

Jiang could publicly retire but remain the real authority from behind-the-scenes, much as his predecessor Deng did.

Jiang could reactivate the Community Party chairmanship Mao Zedong’s old position that Deng eliminated because it concentrated too much power and assume it. Hu would become president but remain the No. 2 power behind Jiang.