The gate of UNESCO. [Photo/CGTN]

The US State Department said on Thursday that the country is withdrawing from UNESCO, the cultural and educational agency of the UN, noting that the move will take effect on Dec 31.

"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 department said.

It added that the US would seek to "remain engaged ...as a non-member observer state in order to contribute US views, perspectives and expertise."

In response, UNESCO Director-General Irina Bokova voiced "profound regret" over Washington's decision to withdraw, saying the move marked a loss for multilateralism and for the UN family.

The US had canceled its substantial budget contribution to UNESCO in 2011 in protest at a decision to grant Palestine full membership.