BAGHDAD, Sept. 6 (UPI) -- Bombings and shootings in Iraq killed a high-ranking Iraqi military officer and five civilians and injured at least 21 people, officials said.

The Iraqi Interior Ministry said gunmen opened fire on the officer, a brigadier general, as he drove his car Monday in the western Baghdad neighborhood of Ameriya, CNN reported.

Local police said five Iraqi construction workers were found dead Monday in Samarra, about 60 miles north of Baghdad. The workers' bullet-riddled bodies were found in their apartment in the center of the city, authorities said.

In western Baghdad's Harthiya neighborhood, attackers using guns fitted with silencers wounded a senior Agriculture Ministry employee as he was leaving his home, CNN said.

Also Monday, a double bombing in western Baghdad's Ghazaliya neighborhood injured at least 15 Iraqis. First, a roadside bomb targeting civilians detonated, then there was another explosion when security forces responded.

In Baghdad's Dora district, a roadside bomb struck a private Iraqi security company's convoy, wounding at least two civilians and damaging one vehicle.

In other attacks, gunmen opened fire on a police checkpoint in western Baghdad, wounding a policeman, and a bomb attached to a civilian vehicle injured its two occupants.

The U.S. military ended its combat role in Iraq last week.