A top al-Sadr aide refuted that statement. The U.S. military also said it could not confirm Iraqi police had taken control of the mosque.
Al-Sadr has said he will hand over control of the mosque to Iraq's most influential Shi'ite cleric, Grand Ayatollah Ali al-Sistani.
Al-Sistani is currently in London where he has been hospitalized with heart problems. His spokesman said al-Sistani had told his aides in Al-Najaf to prepare to accept the keys to the Imam Ali Mosque, if al-Sadr's militia leaves the site.
Amid the persisting confusion, U.S. aircraft resumed operations on the night of 20 August against positions of al-Sadr's militia in Al-Najaf.
For the latest news on Iraq, see RFE/RL's webpage on "The New Iraq".
Factbox: Iraq's Holy City of Al-Najaf