An Israeli group that collects testimonies from combat soldiers has published accounts from last year's Gaza war alleging indiscriminate fire killed Palestinian civilians.

Breaking The Silence said on Monday that its accounts, gathered from dozens of unnamed soldiers, show a "change in the military's combat norms".

"A troubling picture arises of a policy of indiscriminate fire that led to the deaths of innocent civilians," the group's director Yuli Novak said.

The report said that the testimonies came from soldiers who served in the 50-day war between Israel and Hamas, a Palestinian group that rules over Gaza. Soldiers only were identified by their rank and branch of the military they served in to protect their privacy.

The group says its reports, which are critical of the military, are meant to show the Israeli public the difficult "reality" where soldiers serve in Palestinian areas.

More than 2,200 Palestinians, the majority of them civilians, were killed during the war. In Israel, 67 soldiers and six civilians were killed.

The Israeli army said it would investigate all complaints of abuse made against his soldiers.

"The Israeli Defense Force is committed to properly investigating all credible claims raised via media, NGOs, and official complaints concerning IDF conduct during operation Protective Edge, in as serious a manner as possible," it said in a statement sent to Al Jazeera.

The accounts claimed that Israel loosened its rules of engagement, resulting in heavy civilian casualties.

Wartime misconduct

"Anything inside (the Gaza Strip) is a threat, the area has to be sterilised, empty of people and if we don't see someone waving a white flag, screaming, 'I give up', or something then he's a threat and there's authorisation to open fire," one soldier, identified in the report as an infantry sergeant, said.

Others described incidents in which civilians were killed.

The Israeli military has launched dozens of investigations into alleged wartime misconduct. It rejected the group's report, saying the claims lacked proof and could not be investigated.

Israel argues that the heavy civilian death toll was Hamas' fault, accusing it of using civilians as human shields, launching rockets and drawing retaliation from civilian areas.

Still, the report is likely to add fuel to Palestinian claims that Israel committed war crimes during the fighting.

The Palestinian Authority recently joined the International Criminal Court in hopes of prosecuting Israel over alleged war crimes.