Dan Marburger "acted selflessly and placed himself in harm's way" as a 17-year-old opened fire at a school near Des Moines, officials said.

He tried to distract the gunman before being shot, giving students a chance to flee, according to his daughter.

Six others at Perry High School suffered injuries and 11-year-old Ahmir Joliff was killed in the shooting.

The sixth-grader was shot three times, authorities said.

Mr Marburger, who had been head of the school since 1995, died at 08:00 local time on Sunday, his wife Elizabeth wrote on a GoFundMe page launched for his family.

"After 10 days, he lost his battle and this tragedy took his life," the page read.

"Although Dan is no longer fighting with us here, his family will continue to deal with the unfathomable for many days, weeks, and years to come."

Iowa Governor Kim Reynolds said he would "forever be remembered for his selfless and heroic actions".

She ordered flags across the state to fly at half-mast until sunset on the day of Mr Marburger's funeral.

The shooting began at around 07:30 (13:30 GMT) on 4 January in the school cafeteria where pupils were eating breakfast, authorities said.

That is where Mr Marburger intervened and tried to "talk down" the suspect, identified as Dylan Butler.

"It is absolutely zero surprise to hear he tried to approach and talk Dylan down and distract him long enough for some students to get out of the cafeteria," his daughter Clare wrote in a Facebook post. "That's just dad."

Butler, a 17-year-old student, was later found dead at the scene from a self-inflicted gunshot wound.

An Iowa Division of Criminal Investigation spokesman told the AP news agency he had a shotgun and handgun - as well as a "pretty rudimentary" explosive device among his belongings.

The incident took place less than two weeks before Monday's Republican presidential caucuses in Iowa.

Shortly after the shooting, President Joe Biden was briefed and the White House contacted the Iowa governor's office.

By Phelan Chatterjee