Residents said that warplanes struck IS targets in Zummar, a town about 70 kilometres northwest of Mosul, near Badush, a former prison west of Mosul and near a village called Aski Mosul.
Medical sources said the bodies of 25 fighters were brought to the morgue in Mosul, which the jihadist organisation has used as its main centre early June.
It was not immediately clear whether the warplanes were Iraqi or from the US-led international coalition, which carries out daily raids against IS targets in Iraq and Syria.