The board of the UN cultural agency Unesco has agreed to put a Palestinian bid for full membership to member states for approval.
Forty of the 58 board members backed a Palestinian draft resolution proposing membership, with the US among four voting against and 14 abstentions.
The bid will now be put to all 193 member states at the end of the month.
It is a further step in the campaign by Palestinian diplomats for formal recognition as a state.
But their campaign is fiercely opposed by the US, Israel and France, who say only negotiations with Israel can achieve an independent Palestinian state.
US Secretary of State Hillary Clinton on Wednesday described as "inexplicable" Unesco's decision to move ahead on the Palestinian bid.
"I would urge the governing body of Unesco to think again before proceeding with that vote because the decision about status must be made in the United Nations and not in auxiliary groups that are subsidiary to the United Nations," Mrs Clinton said.
Israeli Unesco ambassador Nimrod Barkan said the move would harm the agency and not advance Palestinian aspirations.
France, which abstained on the motion, said "it was not the time" for Palestinians to pursue Unesco membership.
The Palestinians have had observer status at Unesco since 1974.
The US currently pays 22% of Unesco's funding and the latest move raises questions about whether Washington might cut off that funding if the agency accepts the Palestinians as a member.
US Republican Congresswoman Kay Granger, who chairs the sub-committee that disburses US money for diplomatic purposes, said in a statement she would "advocate for all funding to be cut off".
The US Congress recently froze $200m (£130m) US aid to the Palestinian Authority in response to its application for UN membership.
The move was opposed by the US administration and described as a "great disappointment" by the Palestinians.
In September Palestinian President Mahmoud Abbas formally applied for full membership in the United Nations, and that bid is now inching through the procedural channels.
Now Palestinians are pursuing parallel, potentially faster strategies to secure international recognition.
They have applied for full membership of Unesco - the UN Educational, Scientific and Cultural Organisation - before but are now using a different tactic of the draft resolution, Unesco diplomats say.
Correspondents say Unesco membership would allow Palestinians to apply to classify their monuments as World Heritage Sites at a time when the heritage of much of the region is under dispute.
Two-thirds of members attending the Unesco general conference from 25 October to 10 November will have to approve the bid in order for it to be successful.