Militants attacked police stations in the towns of Rawa and Aana near the highway to Syria in Anbar province, and also killed the brother of a local official, the sources said.
Militants including those linked to Al-Qaeda frequently target Iraqi security forces and other government employees.
The violence came after four days of attacks that have raised the spectre of a return to the all-out Sunni-Shiite sectarian conflict that peaked in 2006-2007 and killed tens of thousands of people.
Those attacks were preceded by bombings targeting Shiite mourners in the Iraqi capital on Saturday that killed 73, and two blasts at a Sunni mosque north of Baghdad in which 18 died on Friday.
Violence in Iraq has reached a level this year not seen since 2008, a surge in unrest that authorities have so far failed to stem.
With the latest violence, more than 610 people have been killed this month and over 4,400 since the beginning of the year, according to AFP figures based on security and medical sources.