BAGHDAD, Aug 22: The priceless treasures which have lain for centuries in the mausoleum at the shrine of Imam Ali in Najaf are proving to be a stumbling block for mediators trying to end the siege by rebel Shia militias.

Ayatollah Ali Sistani, Iraq's most respected Shia figure, is holding firm about accepting the keys to the shrine, one of the holiest sites in the Shia world, from rebel cleric Moqtada Sadr until he can be sure all the treasure is safe after the five months the Mehdi Army militia has been holed up inside.

Sistani's office accepted an offer by Sadr on Friday to take control of the shrine to bring an end to the face-off with US forces since August 5. But it has stipulated that before it takes control, an inventory must be carried out to make sure the treasures remain in place and intact.

"The mausoleum contains many items and priceless treasures, which no-one except the Waqf knows the value of," said Salah Abdelrazzak, general manager of Waqf, the Shia religious endowments body.

He gives the example of one of the caves beneath the mausoleum which contains gifts from kings, emirs and leaders of Arab and Muslim countries. "Crowns, swords, jewels, precious stones, gold and silver vases, sumptuous carpets, crystal chandeliers," are all among the valuables, he said.

"When you talk about keys, it is not just the one key but a whole bunch of keys for the outside doors, the strongrooms where the treasures are stored and for the mausoleum itself where pilgrims leave offerings of money," he explained.

With a surface area of 15,000 square metres, the mausoleum has five massive exterior doors guarding the entry to the tomb of Imam Ali, the first Imam to the Shia creed and son-in-law of the Prophet Mohammed.

Sheikh Ali Sumeisim, a close ally of Sadr, is the current guard of the mausoleum. "One of the sets of keys was stolen five months ago by the Mehdi Army from one of the guardians of the mausoleum, Raduan al-Rufai, as he was closing up for the night. Since then, we have no idea what has happened to the treasures," Abdelrazzak said.

The Rufai family, one of the pillars of Najaf society and reputedly descended from the Prophet Mohammed, have been guardians of the site and keepers of the keys since being appointed by the Shia religious authority, the marjaiya, in 1845.

The keys have been handed down from generation to generation. The last "kilidar", or keeper of the keys, living in Iraq was Haidar al-Rufai, murdered in the mausoleum in April 2003, along with Abdel Majid al-Khoi, descendant of Iraq's most authoritive ayatollah, Abul Kassem al Khoi. Moqtada Sadr is accused of being an accessory to both killings.

Raduan al-Rufai was brought back from London, where he had lived for 23 years, to take his cousin Haidar's place but since the theft of the keys, he has lived incognito in Baghdad in the hope of escaping the same fate as his cousin.

Since the start of the clashes with the Americans, the Shia militia has used the edifice for a variety of purposes - as headquarters, as a hospital, press centre, baths, resting place for fighters, a meeting point and a place of prayer.

"We deplore this abuse of the most holy Shia site by the Shias themselves," Abdelrazzak said. Sheikh Sumeisim said on Saturday that Sadr had made it clear to Sistani that they should form "a committee made up of Waqf staff, a Waqf accountant and people he trusts" to evaluate the treasures.

Abdelrazzak believes that Waqf's inclusion in the negotiations is vital. "It is the body which is usually the legal administrator of the mausoleums and Shia holy sites in the country and the only body which holds the complete register of the mausoleum treasures," he said. "We want to take back control of the mausoleum, in conjunction with the governor of Najaf and the marjaiya", represented by Sistani, he said. -AFP