Local councilman Khalid Salman said one of the bombers attacked the gate of the compound and the others struck after soldiers gathered to help the victims. He said eight soldiers were wounded in the attack.
IS claimed the assault in online statements issued on jihadi websites, saying it was carried out by two Syrian suicide bombers. The AP could not confirm the authenticity of the statements, but they resembled previous announcements issued by the group.
Iraqi forces, primarily Shiite militias, meanwhile launched a new push to retake a sprawling desert area outside the central city of Samarra, home to one of Shiite Islam's holiest shrines, officials said.
They hope to cut IS supply lines and tighten the noose around the IS-held northern city of Mosul -- Iraq's second largest -- according to a statement by the Joint Operations Command. The statement said Iraqi warplanes were supporting the mission. It did not say if the US-led international coalition was involved.