In one of the latest reports of deaths, four worshipers were killed as they left Baghdad mosques.
Casualty reports in this week's fast-spreading violence varied.
National police said Thursday the death toll had climbed to 169 with 280 wounded, but there were more deaths Friday, including those at the mosques, and estimates of the toll were as high as 200.
The seizure of the town of Seleiman Beg Thursday by Sunni militants was part of a string of violence that began Tuesday when government troops attacked a Sunni protest site in the central Iraq town of Hawija and killed at least 53 people, Voice of America reported.
Authorities said dozens more were killed in other incidents in western and northern Iraq.
The violence in the country this week was the worst in four months of protests by minority Sunnis, who have demanded the resignation of Prime Minister Nouri al-Maliki, a Shiite, Voice of America said.
Maliki spoke of "a region teeming with sectarianism."
Security forces must impose security in Iraq but the people must come together to end the strife, he said.
Maliki called on individual Iraqis, tribal leaders, members of the clergy and the media to "take the initiative and not be silent about those who want to take the country back to sectarian civil war."