Trouble in Rutbah, in Anbar province near the Jordanian border, started Saturday when Islamic State militants killed a local resident for killing a member of the group as part of a long-running clan blood feud.
Hundreds of residents demonstrated later that day to protest the killing and clashes broke out when the militants attempted to disperse the protesters.
A provincial Anbar official said Saturday some 70 residents were detained by the militants and more than 100 more were tied to streetlight poles for about 24 hours as a punishment.
Demonstrating against the Islamic State group in areas under its control had been rare since the group seized much of northern and western Iraq in the summer of 2014.
The group has zero tolerance for noncompliance with its radical interpretation of Islam or cooperation with authorities in Baghdad, routinely handing down severe punishments like beheadings, burning offenders to death or, in less serious cases, flogging or placing offenders in cages placed at public squares.