An audio tape purportedly from al-Qaeda ally Abu Musab al-Zarqawi has urged insurgents in Iraq to mobilise against US led forces and target supply lines to prevent any attacks on other cities after Fallujah.
"The enemy has amassed all their capabilities and power to eradicate Islam in Fallujah and if the enemy finishes in Fallujah they will move towards you, so be alert and foil this plan," said the speaker, who experts believe sounded like al-Zarqawi.
The authenticity of the tape, posted on a website often used by Islamists, could not be immediately verified.
"The enemy is weak and cannot widen their battle so do not stop at expelling them ... advance towards them and rain rockets and mortars down on them," said the speaker.
The US military says it has taken control of the western city of Fallujah, but scattered resistance remained, particularly in southern parts of the city. The Fallujah offensive has fuelled violence across Iraq's Sunni Muslim heartland, especially Mosul.
"Block off all their main and secondary supply lines for these are their main arteries and ambush them along those routes for they are exposed and easy prey," the speaker said.
Supporters of al-Zarqawi's organisation of Holy War in Iraq are reported to be among insurgents fighting US and Iraqi forces in Fallujah. The group has claimed some of the bloodiest suicide bombings and hostage beheadings in Iraq.