The United Nations' cultural agency will decide later on Monday whether to give the Palestinians full membership of the body, a vote that could boost their bid for recognition as a state at the United Nations.
UNESCO is the first U.N. agency the Palestinians have sought to join as a full member since President Mahmoud Abbas applied for full membership of the United Nations on September 23.
Washington has vowed to veto full U.N. membership for the Palestinians in the U.N. Security Council and could cut funding to UNESCO if it votes to make them full members.
We believe this is counterproductive... The only path for the Palestinians is through direction negotiations, US Undersecretary of Education Martha Kanter told delegates ahead of the vote at UNESCO's General Conference.
We urge all parties to vote with us...against this resolution, she said.
Palestinian Authority Foreign Minister Riyad al-Malki said on Sunday he expected to get the required support.
The Palestinians can join UNESCO if they get backing from two thirds of its 193 members, regardless of their broader status at the United Nations, where they are now classified as an observer entity.
UNESCO said the vote was expected in the middle of the day but could take some time.
Forty representatives of the 58-member board voted in favour of putting the matter to a vote earlier this month, with four -- the United States, Germany, Romania and Latvia -- voting against and 14 abstaining.
Admission will be seen by the Palestinians as a moral victory in their bid for full U.N. membership but could be costly for UNESCO.
Under U.S. law, the admission of Palestine as a full UNESCO member would trigger a cutoff in U.S. funding which accounts for 22 percent of the agency's funding.
Washington says the Palestinian bid for a full U.N. seat is unhelpful to efforts to revive peace talks with Israel, the last round of which broke down a year ago.
Israel has said the Palestinian bid would amount to politicisation of the agency that would undermine its ability to carry out its mandate.
(Reporting By John Irish; editing by Philippa Fletcher)