"If crimes go unpunished, it will happen again. There must be a strong deterrent against these crimes."
Shiite protestors aligned with Muqtada al-Sadr overran Baghdad's heavily fortified Green Zone on Saturday, demanding an end to government corruption.
The Saturday morning attack on an open-air fruit and vegetable market killed at least 19 people and wounded another 40 while popular Shiite leader and cleric Muqtada al-Sadr led his supporters in a protest calling for government reforms.
Shia militias enlisted to fight against the Islamic State are kidnapping and murdering hundreds of mostly-Sunni victims with impunity, according to a new Amnesty International report.