The mass rallies rocking Iraq's capital and south have been met with violence by security forces and armed groups, leaving nearly 430 dead and 20,000 wounded.

The protest have been concentrated in Shiite Muslim-majority areas, but on Tuesday, a large part of Iraq's Christian community said it would take part in an act of solidarity.

"There will be no decorated Christmas trees in the churches or streets, no celebrations and no reception at the patriarchate," announced the head of Iraq's Chaldean Catholic community, Patriarch Louis Raphael Sako.

Iraq's Christian minority has been ravaged by years of war, with just a third left out of the 1.5 million Christians living in the country before 2003.

Many are in Baghdad or the northern province of Nineveh.

Sako made the decision "out of respect for the dead and wounded among protesters and security forces, and in solidarity with the pains of their families".

As the demonstrations enter their third month, other non-Shiite communities in Iraq have also expressed solidarity.

Sunni-majority Mosul has held funeral marches for those wounded further south and Salahaddin province announced three days of mourning for the fallen.

Hundreds of students also marched in multi-ethnic Kirkuk.