The State Department cited "continuing anti-Israel bias" for its decision
The US State Department has announced that the country will be withdrawing from UNESCO.
UNESCO - or the United Nations Educational, Scientific and Cultural Organisation - works to achieve "international cooperation in education, science, culture and communication", and has almost 200 member states.
As well as a variety of educational initiatives, its key functions include designating World Heritage Sites - sites which are deemed to have historic, scientific or cultural significance.
The US withdrawal from the international organisation will be effective from the end of 2018.
The country had previously withdrawn from UNESCO for almost two decades from 1984, but rejoined in 2003.
UNESCO Director-General Irina Bokova expressed 'profound regret' at the US decision:
In a statement, US State Department spokesperson Heather Nauert cited 'anti-Israel bias' and the organisation's 'mounting arrears' for its decision to withdraw from UNESCO.
She explained: "The Department of State notified UNESCO Director-General Irina Bokova of the US decision to withdraw from the organisation and to seek to establish a permanent observer mission to UNESCO.
"This decision was not taken lightly, and reflects US concerns with mounting arrears at UNESCO, the need for fundamental reform in the organization, and continuing anti-Israel bias at UNESCO."
The statement adds that the US wants to serve as a "non-member observer state in order to contribute US views, perspectives and expertise on some of the important issues undertaken by the organisation".
It will remain a full member of UNESCO until December 31st 2018.
Israel welcomed the move, with Prime Minister Benjamin Netanyahu office suggesting the country is also preparing to withdraw.
In a statement quoted by The Times of Israel, Mr Netanyahu said: "This is a courageous and moral decision because UNESCO has become the theater of the absurd and because, instead of preserving history, it distorts it.”