JERUSALEM - Israeli troops were repeatedly encouraged by officers to prioritise their own safety over that of Palestinian civilians when they embarked on the ground invasion of Gaza in January, according to the first direct testimonies of soldiers who served in the operation.

The picture that emerges from the testimonies is one of massive fire power to cover advances and rules of engagement that were calculated to ensure, in the words attributed to one battalion commander, that "not a hair will fall of a soldier of mine. I am not willing to allow a soldier of mine to risk himself by hesitating. If you are not sure, shoot."

The first eyewitness accounts of the war by serving Israeli reservists and conscripts describes the Israeli use of Palestinian civilians as "human shields".

They detail the killing of at least two civilians, the vandalism, looting and wholesale destruction of Palestinian houses, the use of deadly white phosphorus, bellicose religious advice from Army rabbis and what another battalion commander described to his troops as "insane firepower with artillery and air force".

The reports amount to the most formidable challenge by Israelis since the Gaza war to the military's own considered view that it conducted the operation according to international law and made "an enormous effort to focus its fire only against the terrorists whilst doing the utmost to avoid harming uninvolved civilians".

They are contained in testimonies from about 30 soldiers that were collected by Breaking the Silence, an Army veterans organisation that seeks to "expose the Israeli public to the routine situations of everyday life in the occupied territories".

Although the organisation has collected hundreds of testimonies from ex-soldiers before, this is the first time that it has done so from serving soldiers so soon after the events they describe. They tell how:

Unprecedentedly loose rules of engagement were put in place to protect Israeli troops. One soldier said his brigade commander and other officers made it clear that "any movement must entail gunfire". He added: "I don't remember if the brigade commander said this or someone else. No one is supposed to be there. If you see any signs of movement at all, you shoot. These, essentially, were the rules of engagement."

Houses were systematically demolished. Despite official accounts that homes were only destroyed for strictly "operational" reasons, one reservist, a veteran of the conflict in Gaza since before 2005, said "I never knew such fire power" used by tanks and helicopters for the "constant destruction" of houses.

A civilian man between 50 and 60 who was unarmed but carrying a torch was shot dead after the unit's commander ordered his soldiers not to fire warning shots but to hold their fire until he was 50m away. The soldier said the company commander announced over the radio after the incident: "Here's an opener for tonight". The soldier said that the commander was challenged over why he had not authorised deterrent fire when the man was further away: "He didn't agree and couldn't give a damn, and finally the guys felt that even if they could take this up with the higher echelons it wouldn't be effective."