Before the start of the conflict, Qusayr was home to about 60, 000 people, mostly Sunni Muslims and Christians.

WSJ: Syrian Forces Push to Retake Rebel Stronghold

Mostly Sunni Muslims live in the neighborhood, which is surrounded by walls except for one checkpoint staffed by Iraqi soldiers.

CNN: Blast in popular Baghdad coffee shop kills at least 27

The alliance campaigned on a platform of a unified Iraq in the March 2010 elections, but lost by a mere two seats to the mostly Sunni-backed al-Iraqiyya alliance of former Prime Minister Iyad Allawi.

BBC: Profile: Nouri Maliki

The population is 89% Shia Muslim, 10% Sunni (mostly Kurds) and 1% Zoroastrian, Bahai, Jewish or Christian.

ECONOMIST: The trials of everyday life

The committee would be formed mostly of Mr. Maliki's Shiite coreligionists and Saleh Al Mutlaq, a Sunni ally of Mr. Maliki's.

WSJ: Clashes at Iraq Sunni Protest Kill 38

Mr. Maliki said he would convene a committee to investigate Tuesday's violence that would include mostly of Mr. Maliki's Shiite coreligionists and Saleh al-Mutlaq, a Sunni ally of Mr. Maliki's.

WSJ: Iraq Makes a Deadly Raid on Protest Camp