There will be no new UNESCO projects this year, following a cut in funding by the United States.
Since UNESCO granted full membership to the Palestinians last month, Washington has withdrawn its support, along with Israel and Canada.
The UN’s cultural agency, whose tasks include protecting heritage sites and working to improve literacy, has appealed to other member countries to donate more.
America is responsible for contributing a fifth of the organisation’s money and UNESCO’s director general said the agency now has a funding gap of over 105 million euros.
According to US law, money cannot be given to any branch of the UN that gives full membership to a group not internationally recognised as a state, such as the Palestinians.