JERUSALEM (Reuters) - Israel said on Monday it had canceled a visit by the United Nations Educational, Scientific and Cultural Organization (UNESCO) to Jerusalem's Old City, saying the Palestinians had sought to politicize a conservation mission.

No one was immediately available for comment at UNESCO's Paris headquarters. A month ago, it announced it would send experts to Jerusalem in mid-May to examine the state of conservation of the walled Old City, a World Heritage site.

The future of the Old City, in a part of Jerusalem that Israel captured in the 1967 Middle East war and annexed in a move that is not recognized internationally, is a highly sensitive issue at the heart of the Middle East conflict.

An Israeli official said Israel objected to Palestinian Foreign Minister Riyad al-Malki's reference to the UNESCO tour as a "probe (of) the occupation measures" in the city.

"The Palestinians have violated all the understandings reached, and made real attempts to change the visit from a professional to a political visit," the official said. "So we are calling off (the visit)."

Israel had given a green light to what would have been UNESCO's first mission to Jerusalem since 2004, in exchange for its agreement to avoid anti-Israeli motions at a conference next month in Cambodia where the team's findings were to be submitted, officials said.

Palestinian official Ismail Al-Tellawi also confirmed to Reuters that UNESCO's visit had been delayed indefinitely.

He cited "differences (with Israel) over some of the places the investigation committee intended to visit".

The Israeli official said the Palestinians had wanted to take the UNESCO representatives to the Old City compound revered by Muslims as the Noble Sanctuary, because it is home to the Dome of the Rock shrine and the al-Aqsa mosque, and by Jews as Temple Mount, the site of the great biblical Jewish temples.

(Additional reporting by Ali Sawafta in Ramallah; Editing by Jeffrey Heller and by Kevin Liffey)