Confusion now shrouds a US claim on Thursday that Iraq's supreme Shi'a Muslim cleric had issued a religious decree calling on the populace not to impede coalition forces.
Najaf is still not fully secure, and it is difficult to get accurate information out
The US Central Command on Thursday said the Grand Ayatollah Mirza Ali Sistani had instructed the Iraqi people "to remain calm and to not interfere with coalition actions".
Such an edict would be a significant blow to Saddam Hussein's efforts to enlist the support of Shi'a Muslims and other Muslim Arabs in his battle against coalition forces and to present the conflict as a "holy war".
But his son-in-law and spokesman, Ayatollah Sharestani, who is based in the Iranian holy city of Qom, could not confirm that any such fatwa had been issued.
That implied that a contradictory exhortation by Grand Ayatollah Sistani last week to stand up against invading forces still stood, despite the fact it could have been issued under duress from pro-Saddam Hussein militias.
Other commentators suggested there is internal confusion among the Shi'a clerical community in Iraq over whether - or when - to risk telling followers not to fight to save Saddam Hussein.
Coalition forces in the last Gulf war notoriously failed to support an uprising by retreating Iraqi soldiers and Shi'a Muslims against Saddam Hussein's Baath party, rooted in Sunni Islam.
The uprising was harshly repressed.
Iraqi Information Minister Mohammed Saeed al-Sahhaf said the "fatwa" was a fabrication by the coalition, and said prominent Shi'a clerics had in fact urged followers to fight the invasion.
The London-based Al-Khoei Foundation - a Shi'a charity and Iraqi opposition organisation - initially appeared to back up assertions by US Central Command that a fatwa urging compliance with coalition troops.
On Friday morning, however, the foundation appeared to backtrack, saying they were as yet unable to confirm the existence of any fatwa.
Our religious affairs correspondent, Jane Little, says the confusion is a reflection of how important the grand ayatollah is to the Shi'a community - and by extension to the Americans, who hope the Shi'a will rise up in support.
Najaf is one of the holiest cities in Shi'a Islam and its shrine to Imam Ali is highly revered.
Coalition forces are still rooting out pro-Saddam fighters in Najaf.