UNITED NATIONS, NOV. 13 -- A top aide to U.N. Secretary General Javier Perez de Cuellar has withdrawn his candidacy for High Commissioner for Refugees and suggested that opponents were motivated by possible racism and anti-Third World bias.

The charges are the latest installment in an unprecedented and frosty exchange between the U.S. and other major donors and the secretary general. Until now, U.S. relations with Perez de Cuellar have been described as warm.

But on Monday, the secretary general issued a statement saying he was "pained and profoundly irritated" by news reports quoting U.S. officials that portrayed the candidacy of Virendra Dayal, his chief of staff, as "cronyism."

The tension comes as the United States has been placing increased emphasis on the United Nations as a means of maintaining the international coalition against Iraqi leader Saddam Hussein. While the dispute is not expected to have any impact on that U.S. diplomacy, the sharp tone of the exchange caught many diplomats by surprise.

"Given the present controversy as to whether a non-European can be worthy of the post, which I find demeaning, I would appreciate it if my name could be withdrawn from consideration," said Dayal, an Indian national, in a letter to the secretary general. "There is no way in which I can develop the attributes of a Western European politician, whether in or out of office."

Dayal, who is Perez de Cuellar's chief of staff, was referring to reports that the major donor countries favor the appointment of a prominent political figure capable of raising money for the financially strapped agency, which is responsible for protecting 15 million refugees.

Criticism of Dayal's candidacy became public after officials from the United States and other countries were reported to be opposed to the appointment of Dayal because Perez de Cuellar had failed to adequately consult donor nations.

Some diplomats said the dispute was not about Dayal but about the way the secretary general set out to promote his candidacy.