"Yesterday afternoon a number of tribal leaders entered Najaf," Mohammed Baqer Musawi al-Muhri told AFP.

He said the intervention by tribal leaders, who are mainly from the central Euphrates region, had put an end to the presence of roughly 50 armed men around the house of Ayatollah Ali Sistani.

Muhri said the armed men had gathered on Saturday and demanded Sistani leave Iraq within 48 hours.

He also said in a statement Sunday that the gunmen were from the same group that murdered prominent pro-Western Shiite cleric Sayyed Abdul Majid al-Khoei in Najaf on Thursday, just a week after he returned to the city from London with the help of US forces who invaded Iraq.

Muhri said the tribal leaders wanted to ensure the safety of all religious clerics and leaders in Najaf, particularly Sistani.

The tribes come from areas in Iraq such as al-Shamiya and al-Abbas, said Muhri, who heads an association of Shiite scholars in Kuwait.

Sistani was still inside his home Monday but "out from danger", which had been dramatically reduced by the tribal leaders' presence, he said.

Muhri's earlier statement said the gunmen had given Sheikh Is'hak Fayyad, an Afghan-born Shiite religious scholar also based in Najaf, the same ultimatum to leave Iraq.

But a spokesman for the accused group denied the charge, which had fueled speculation about mounting rivalry among Shiite factions after the downfall of Saddam Hussein's regime.

"I categorically deny (the claim) that ... (Muqtada) Sadr delivered an ultimatum to Ayatollah Sistani" to leave Iraq, Riyad al-Nouri told the Qatar-based al-Jazeera satellite channel.

Muhri said the group threatening the clerics comprised followers of Muqtada al-Sadr, the 22-year-old son of Mohammed Sadeq al-Sadr, a senior Shiite authority assassinated in 1999.

His statement also charged the group was targetting another Shiite cleric in Najaf, Sayyed Mohammad Said al-Hakim, threatening unspecified punishment unless he pledged allegiance to Muqtada al-Sadr.

Hakim is the nephew of Ayatollah Mohammad Baqer al-Hakim, who heads the Tehran-based Supreme Assembly of the Islamic Revolution in Iraq (SAIRI), the main Shiite Islamist group that opposed the ousted Saddam regime.

The accusations underscored inter-Shiite rivalries for religious and political supremacy in Najaf following the collapse of Saddam's regime.

SPACE.WIRE