BAGHDAD – Iraqi troops opened fire on stone-throwing Sunni demonstrators in the country’s restive west Friday, leading to the deaths of at least five protesters — the first fatalities in more than a month of anti-government rallies. Two soldiers were also killed, apparently in retaliation.

The violence is likely to exacerbate tensions between the Shiite-led government and minority Sunnis angry over perceived second-class treatment and what they see as unfair policies targeting their sect.

Hours later, police said gunmen attacked an army checkpoint, killing the soldiers, in apparent payback for the earlier bloodshed. An army vehicle was set ablaze, and dozens of civilian gunmen were seen roaming the streets before local authorities imposed a curfew in the city.