Describing the offensive as a genocide, an independent Islamic party on Tuesday denounced the offensive as the "brutal slaughter of civilians".
Hizb-ut-Tahrir spokesman Imran Wahid said Muslims in Britain "must be the voice of the Muslims of Falluja against this brutal genocide and the silence of the spineless rulers of the Muslim world".
"Muslims in Britain call upon the people of the West to question the militancy of Western foreign policy across the globe and the continued interference of their government in the Muslim world," he said.
Condemnation also came in from the Muslim Council of Britain (MCB), which described the assault as a "ghastly counterproductive move to pro-democracy efforts".
"It is highly improbable that the US army is going to help usher in an era of liberation and democracy in Iraq by terrorising and killing its citizens in this ghastly manner," MCB secretary-general Iqbal Sacranie said.