UNITED NATIONS — The most senior American official in Secretary-General Annan’s administration, Christopher Burnham, tendered his resignation yesterday, a move seen by many as a signal to other top U.N. officials to clear the way for the incoming Turtle Bay chief, Ban Ki-moon, to pick a new team.

Mr. Burnham’s resignation will take effect on November 15, six weeks before Mr. Annan is scheduled to leave office after 10 years at the helm of Turtle Bay. Yesterday, both the secretarygeneral and American ambassador to the United Nations, John Bolton, hailed Mr. Burnham’s contribution to the cause of reforming the United Nations as undersecretary-general for management.

Americans in the past have led the management department, which is responsible for overseeing the U.N. bureaucracy, but that could change now. Washington has been lobbying Mr. Ban to appoint an American as head of the fast-growing and increasingly influential peacekeeping department, two U.N. insiders who spoke on condition of anonymity said. The current head of that department is Jean-Marie Guéhenno of France.

A spokesman for Mr. Annan, Stephane Dujarric, said recently that on the U.N. side, an American adviser to the secretary-general, Robert Orr, and the current U.N. chief of staff, Alicia Barcena of Mexico, will lead the transition team. Mr. Orr and Ms. Barcena, along with two Korean advisers to Mr. Ban, are expected to form the next U.N. administration.

Mr. Bolton has said in the past that all top U.N. officials should resign before the transition to allow Mr. Ban to pick his own team. The ambassador lauded Mr. Burnham yesterday and said in a statement that over the next few weeks “we expect many other senior U.N. officials to transition out as well, and we thank all of them for their service.”

Mr. Burnham assumed his post in June 2005, at the height of the oil-for-food scandal. Since then he as attempted to rein in the unwieldy U.N. bureaucracy, which has been beleaguered by corruption, mismanagement, and lax ethics throughout Mr. Annan’s second term.

An investment banker who became the treasurer of Connecticut, Mr. Burnham was the top management official at the State Department before assuming a similar position at Turtle Bay. He plans to resume a private career, Mr. Annan said in a statement yesterday.

Mr. Annan noted yesterday that Mr. Burnham created a U.N. ethics office and enacted a new whistleblower protection policy at Turtle Bay. He also requested that all top U.N. officials report their finances in a financial disclosure form, including gifts worth more than $250.

Under pressure, Mr. Annan finally handed in his own disclosure form earlier this month, but he refused to release it to the public, saying he needed to protect his successor from such a precedent. Mr. Ban told The New York Sun recently that he has no problem making his financial records public.