On Saturday, Iraq has recorded 4,644 new coronavirus cases and 63 deaths in the last 24 hours, bringing the total cases in the country to 256,719 and 7422 deaths.
Some Iraqi authorities warned that hospitals may "lose control" in the coming days.
The health ministry attributed the spike to recent "large gatherings" that took place without recommended safety measures, including mask-wearing or social distancing.
The events included the marking on August 30 of Ashoura, a significant Muslim day of mourning that commemorates the killing of Prophet Muhammad's grandson Hussein in 680 AD.
On that day, tens of thousands of Shia Muslims converged on the holy city of Karbala in southern Iraq.
Karbala's authorities introduced new measures to stem the spread of the virus, including restricting access to areas of worship and widespread spraying of disinfectants.
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But the health ministry warned the measures were not enough.
"The number of cases is expected to escalate further in the coming days, which we fear will lead our health institutions to lose control as they try to deal with these large numbers," its statement said on Friday.
"This will lead to an increase in the number of deaths, after we made headway in reducing them over the past few weeks."
Iraq's hospitals have already been worn down by decades of conflict and poor investment, with shortages in medicines, hospital beds and even protective equipment for doctors.
Before Ashoura, the World Health Organization had warned that COVID-19 cases in Iraq were rising at an "alarming rate" and said Iraq should take action to end the community outbreak "at all costs".