The top U.N. human rights official urged negotiators from more than 100 countries to work beyond their Friday midnight deadline to reach accord on documents for the World Conference Against Racism, which is threatened with a U.S. boycott.

"I make a strong appeal today to everyone" to continue negotiations so that the conference starting Aug. 31 in Durban, South Africa, can be a success, U.N. High Commissioner for Human Rights Mary Robinson said Thursday.

But U.S. Congressman Tom Lantos, the ranking Democrat on the House International Relations Committee who has been in Geneva this week to push for a compromise, expressed doubts that differences could be worked out to make it possible for the U.S. government to attend.

The United States has threatened to boycott the Durban meeting if anti-Israel references in the conference declaration are not removed. The European Union is also pushing for the removal of references to the Middle East.

Arab countries, however, continue to insist that the conference accuse Israel of racism in its treatment of Palestinians.

Lantos said he found Arab delegations unwilling to back off from criticism of Israel in the conference's proposed final declaration. Their latest suggested wording "is dripping with hate," he said.

Unless the anti-Israel wording is removed, Lantos said, "it would be inappropriate" for Secretary of State Colin Powell "to dignify the conference with his presence."

Lantos said he had been trying to make the point that no nation should be singled out because racism is a problem that they all have.

Robinson has been appealing for an open discussion of all issues at Durban, but she has warned against any attempt to revive a U.N. resolution that equated Zionism, the movement the led to the founding of Israel, with racism.

Arab countries, however, continue to insist that the conference accuse Israel of racism in its treatment of Palestinians.

Arab diplomats at the preparatory meeting have rejected U.S. and Israeli arguments that it was unacceptable to single out Israel alone for criticism. Previous conferences have spotlighted countries like South Africa, they said.

Robinson said those working on the draft text should consider "the historical wounds of anti-Semitism and of the Holocaust, on the one hand, and ... the accumulated wounds of displacement and military occupation on the other."

She said also that diplomats drafting the conference declaration should condemn "terrorism, indiscriminate violence, excessive and disproportionate use of force and the propagation of hatred -- by whomsoever committed."

U.N. officials said they thought another key issue of concern to Europe and the United States — Africa's demand for compensation for slavery and colonialism — were near resolution, but details were not yet available.

But the United States is insisting that the contentious issues should be removed this week, even if some final polishing of the text is to be put off until Durban.

Israeli officials say that they, too, would have to consider pulling out of the conference if the deadlock remains by week's end.