Changes to Istanbul's Hagia Sophia could trigger heritage review -UNESCO

PARIS, July 9 (Reuters) - UNESCO must be notified of any change in the status of Istanbul's sixth-century Hagia Sophia museum and the changes may have to be reviewed by its World Heritage committee, the United Nation's cultural body said on Thursday.

Turkey's top administrative court is likely to announce on Friday that the 1934 conversion of the Hagia Sophia into a museum was unlawful, two Turkish officials said, paving the way for its restoration as a mosque.

UNESCO told Reuters that the Hagia Sophia was on its list of World Heritage Sites as a museum, and as such had certain commitments and legal obligations.

"Thus, a state must make sure that no modification undermines the outstanding universal value of a site listed on its territory," UNESCO said.

"Any modification must be notified beforehand by the state to UNESCO and be reviewed if need be by the World Heritage Committee," it added.

The World Heritage site was at the centre of both the Christian Byzantine and Muslim Ottoman empires, and is today one of Turkey's most visited monuments.

The prospect of a change in the museum's status back to a mosque has raised alarm among U.S., French, Russian and Greek officials as well as Christian church leaders. (Reporting by Leigh Thomas Editing by Sonya Hepinstall)