According to a statement by the PMU media office, a combined force of the government army and PMU (also known as Hashd Shaabi) fighters killed the three militants after pursuing them in a desert region west of the provincial capital Mosul, around 400 km north of Baghdad.
Four Hashd Shaabi fighters were also wounded in the operation, the statement said.
The force also seized a vehicle used by the terrorists that contains explosive belts, weapons and ammunition, it added.
Over the past months, Iraqi security forces have conducted operations against the terrorists to crack down on their intensified activities.
The security situation in Iraq has been improving since the defeat of Daesh in 2017. However, its remnants have since melted into urban centers, deserts, and rugged areas, carrying out frequent guerilla attacks against security forces and civilians.