The United States has notified the United Nations Educational, Scientific and Cultural Organisation (UNESCO) that it is pulling out to assume a stance as a “permanent observer”, instead of an active member of the organization.

Heather Nauert, US State Department spokeswoman, said the country would establish an “observer mission” to replace its representation at the Paris-based agency.

The country cited UNESCO’s “anti-Israel bias” as its reason for pulling out of the organization.

The US was irked in 2011 when UNESCO granted Palestine full membership of the body, despite opposition from Israel, a close ally of the US.

In a statement on Thursday, Nauert said the withdrawal is to take effect by December 31, 2018.

“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 read.

“The United States indicated to the director-general its desire to remain engaged with UNESCO as a non-member observer state in order to contribute US views, perspectives and expertise on some of the important issues undertaken by the organization, including the protection of world heritage, advocating for press freedoms and promoting scientific collaboration and education.”

This development comes as UNESCO vote to select a new director general this week.