The al-Jazeera satellite television channel said today it had received a statement from Osama bin Laden urging Muslim solidarity with Iraq and would broadcast it later in the day.
Al-Jazeera said the statement "urged Muslims to show solidarity and defend the Iraqi people".
"We have a statement and we will show it later tonight. It has a message," editor Mr Saeed al-Shouly told Reuters.
Earlier today US Secretary of State Colin Powell told the US Senate Budget Committee that he had read a transcript "of what bin Laden, or who we believe to be bin Laden, will be saying on al-Jazeera during the course of the day".
Statements from bin Laden have often been issued to confirm attacks blamed on his al Qaeda network.
The United States raised its national threat alert level last week to orange - the second highest - citing intelligence reports of a threat from groups linked to al Qaeda.
The United States says it does not know where bin Laden is, or whether he is alive or dead, after he evaded capture in Afghanistan in 2001. But US officials said last year an audio recording broadcast on al-Jazeera in November and purported to be from bin Laden was almost certainly genuine.
The tape was considered the strongest evidence so far that bin Laden survived the war in Afghanistan.
Al-Jazeera has often received audio tapes and statements said to come from bin Laden, blamed for the September 11th attacks on US cities. The United States has accused the Arab TV channel of being a mouthpiece for al Qaeda propaganda.