Four protesters were killed by tear gas canisters in Baghdad on Thursday, medics told AFP, the latest deaths from what rights groups have slammed as a "gruesome" misuse of the weapon.
The medical sources said the protesters were hit near Tahrir (Liberation) Square, the epicentre of the weeks-long movement for sweeping political reform.
The United Nations had already documented 16 deaths from the military-grade canisters, which are up to 10 times heavier than regular tear gas grenades and can pierce skulls or lungs.
Amnesty International found that demonstrators suffered "gruesome wounds and death after the grenades embed inside their heads."