ASHINGTON — The Bush administration, embroiling itself in a new fight at the United Nations, has threatened to withdraw its support for a landmark family planning agreement that the United States helped write eight years ago.

The reason for the threat is contained in two terms that the administration contends can be construed as promoting abortion.

The terms — reproductive health services and reproductive rights — figure in the final declaration of the United Nations population conference in 1994 in Cairo, which embraced a new concept of population policy based on improving the legal rights and economic status of women. The declaration has since been endorsed by 179 nations.

But during a population and development conference in Bangkok this week, the American delegation announced that Washington would not reaffirm its support for the Cairo "program of action" unless the disputed words were changed or removed, United States and United Nations officials said.

The threat startled members of other delegations attending the Asian and Pacific Population Conference and drew immediate criticism from Chinese, Indian and Indonesian officials, who argued that the American position would undermine a global consensus on population policy, according to United Nations officials.

The threat has also elicited a sharp response from some Europeans.

"I think it is disappointing and incredible," said Agnes van Ardenne, the Dutch minister for development cooperation. "Poverty reduction will not be successful without reproductive health and without women being able to make their own choices."

Congressional Democrats and United Nations officials underscored these concerns today, saying that a decision by the administration to withdraw support for the Cairo program would undermine the efforts of family planning officials in countries that have looked to the United States to take the lead in checking population growth.

"The impact of these public statements is devastating and could undermine 10 years of work," Representative Carolyn Maloney, Democrat of New York, said in a draft letter to Secretary of State Colin L. Powell that she began circulating on Capitol Hill today. "It is likely that repressive countries will follow the U.S. in its decision and the progress that has been made will cease."

The State Department declined to comment on the dispute today. But administration officials acknowledged that the United States might not reaffirm its support for the Cairo program unless the disputed phrases were withdrawn or modified.

The 1994 conference was widely considered a watershed event because it moved away from traditional ideas of family planning and embraced the idea that giving women more control over their lives would provide a check against explosive population growth.

The program of action called for stabilizing the world's population at no more than 9.8 billion by 2050 and it urged countries to make health care widely accessible, reduce maternal mortality, provide universal access to primary education and stem the spread of H.I.V. and AIDS. The program also suggested that where abortion is legal, it should be made safe.

The program's acknowledgment that legal abortion could be part of health care has drawn objections from the Vatican and several Muslim and Latin American countries. But over the years, the United States has consistently reaffirmed the Cairo principles.

One of the Vatican's chief negotiators in Cairo, John Klink, was an adviser to the United States delegation in Bangkok, United Nations officials said.

Douglas Johnson, legislative director of the National Right to Life Committee, praised the Bush administration's stand.

"We certainly approve of any effort by the administration to make it clear that abortion is not an acceptable method of family planning," Mr. Johnson said. "There is a sort of code used in some of these U.N. documents, and groups that advocate expanded access to abortion do construe these phrases to include abortion."

The dispute over the Cairo program is only the most recent example of administration efforts to withdraw American support from United Nations programs that it contends promote abortion.

In July, the administration decided to withhold $34 million in previously approved aid to the United Nations Population Fund, contending that the agency helps Chinese government agencies that force women to have abortions.

In May, during the United Nations General Assembly's special session on children, the Bush administration, the Vatican and some Muslim countries unsuccessfully pushed for a policy to prevent teenagers from getting abortions. The group also sought to make abstinence the centerpiece of sex education for unmarried teenagers.

Timothy E. Wirth, the under secretary of state for global affairs in 1994, said he expected the Bush administration to reaffirm the Cairo program eventually. If it does not, he said, the United States might alienate important allies just as it is trying to build international support for its Iraq policies.

"The reaction would be very negative," Mr. Wirth added, "at a time when the administration is trying to put together international coalitions on various efforts."

By James Dao