The curfew was to come into force at 6:00 pm and remain in place until 6:00 am Monday, police said.
Riots broke out in the oil-rich city after several hundred demonstrators took to the streets in the mainly Kurdish northern district of Rahimawa to protest the lack of basic services and especially the lack of fuel.
One person was killed and four injured in clashes with police in the town some 255 kilometres north of Baghdad.
“The citizens have a right to protest, but these have turned violent and people have been hurt,” said police Brigadier-General Munis Isahak.
“A lot of our vehicles have been damaged,” he added.
US helicopters buzzed the district, but US soldiers standing by, a short distance away, did not intervene.
The violent protest was one of several across the country in the past few days where fuel distribution has been disrupted by insurgent attacks and threats against oil tanker truck drivers.
