Protesters in the Sunni-dominated Anbar province held signs and chanted slogans against the government of Iraqi Prime Minister Nouri al-Maliki, a report from Voice of America said.
Tensions between Sunnis and Shiites were inflamed last week when bodyguards of Sunni Finance Minister Rafia al-Issawi were arrested. Some saw the arrests as politically motivated.
Protesters blocked main roads in Anbar province and said they won't down until the government changes terrorism laws and releases Sunni prisoners.
Protests were reported in Fallujah, Mosul, Tikrit, Samarra and other locations to mark what Sunni organizers called "Friday of Honor."