A UNESCO convention that allows countries to protect their music, movies and other cultural activities will formally come into force next March after European Union nations ratified the treaty today (Dec. 19) in Brussels.

The convention on cultural diversity, drafted by the United Nations Educational, Scientific and Cultural Organization, aims to consolidate the protection countries sometimes use to block music and movie imports, and strengthen rules on subsidies and quotas.

It was adopted in 2005 in the face of strong protests from the United States, which claimed that the convention would be used to erect barriers against its huge entertainment industry exports. However, it was eventually approved by 148 of the 154 UNESCO members. The EU ratification means the threshold of 30 member confirmations has been reached for it to become a legal instrument.

The 40-page treaty upholds the "sovereign right" of countries to protect and promote the diversity of cultural expressions and requires this to be taken into account in applying other accords, such as the rules of the World Trade Organization.

It does not create any new laws or instruments to protect music or movies, but the U.S. fears it could override the existing conventions that allow American entertainment to be sold to the world.