There are conflicting reports coming out of the Iraqi city of Karbala, where witnesses say gunmen opened fire on anti-government protesters overnight Tuesday, killing 18 and wounding hundreds.
One report puts the number of wounded at a staggering 865.
Some witnesses say the gunmen were Iraqi security forces or riot police while others say they were masked.
Karbala's governor along with senior officials in Baghdad deny anyone was killed. Karbala is one of Islam's holiest cities and the bloodshed could add more fury to the protests.
United Nations officials in Iraq condemned the violence. The human rights group Amnesty International says "These scenes are all the more shocking as they come despite assurances from Iraq authorities that there would be no repeat of the extreme violence used against demonstrators during protests earlier this month."
The U.S. State Department has not commented on the latest reports from Karbala, but has called on all sides to reject violence. It also criticizes what it says are Iraqi government efforts to pressure the media to censor reports about the demonstrations.
Anti-government demonstrators in Karbala, Baghdad, and elsewhere ignored an overnight curfew Tuesday, demanding the government resign.
Students and other protesters are angry at alleged corruption, a slow economy, and poor government services despite Iraq's oil wealth.
A move in parliament to approve a bill to cancel privileges and bonuses for senior politicians, including the president, prime minister and Cabinet ministers, did little to calm the marchers.
The latest wave of violent protests across Iraq has killed at least 86 people since last Friday. That is on top of the nearly 150 killed during marches earlier this month.