JERUSALEM ( CNN ) -- The Israeli military 's firing of white phosphorus shells over densely populated areas during the Gaza offensive `` was indiscriminate and is evidence of war crimes , '' Human Rights Watch ( HRW ) said in a report on Wednesday . Human Rights Watch says Israel used white phosphorus shells over populated areas in Gaza . `` In Gaza , the Israeli military did n't just use white phosphorus in open areas as a screen for its troops , '' said Fred Abrahams , a HRW senior emergencies researcher . `` It fired white phosphorus repeatedly over densely populated areas , even when its troops were n't in the area and safer smoke shells were available . As a result , civilians needlessly suffered and died . '' Entitled `` Rain of Fire : Israel 's Unlawful Use of White Phosphorus in Gaza , '' the 71-page report provides `` witness accounts '' and `` presents ballistics evidence , photographs , and satellite imagery , as well as documents from the Israeli military and government . '' HRW is an independent international organization dedicated to defending and protecting human rights . The group urged Israel and the United States to investigate the attacks . Israel should prosecute those who carried them out and the U.S. government , which supplied Israel , should look into the issue . HRW said white phosphorous was a chemical substance dispersed in artillery shells , bombs and rockets , used primarily to obscure military operations . `` ( While ) it is not considered a chemical weapon and is not banned per se , it ignites and burns on contact with oxygen and creates a smokescreen at night or during the day to mask the visual movement of troops . `` It also interferes with infra-red optics and weapon-tracking systems , thus protecting military forces from guided weapons such as anti-tank missiles . When WP comes into contact with people or objects , though , it creates an intense and persistent burn . It can also be used as a weapon against military targets , '' the group said . In response , the Israeli military said `` smoke shells are not an incendiary weapon '' and defended its actions . The Israel Defense Forces said it was close to completing its probe into `` the use of ammunition containing elements of phosphorous . '' `` ( The invesitgation ) is dealing with the use of ammunition containing elements of phosphorous , including , among others , the 155mm smoke shells which were referred to in the HRW report . This type of ammunition disperses in the atmosphere and creates an effective smoke screen . It is used by many Western armies . `` It is already possible to conclude that the IDF 's use of smoke shells was in accordance with international law . These shells were used for specific operational needs only and in accord with international humanitarian law . The claim that smoke shells were used indiscriminately , or to threaten the civilian population , is baseless , '' the IDF said . It said `` that weapons intended for screening are not classed as incendiary weapons . '' But Abrahams said past IDF investigations into allegations of wrongdoing suggest their inquiry would be neither thorough nor impartial . `` That 's why an international investigation is required into serious laws of war violations by all parties . `` For the needless civilian deaths caused by white phosphorus , senior commanders should be held to account , '' Abrahams said . The report said white phosphorus munitions were n't illegal when deployed properly in open areas , but it determined that the IDF repeatedly used them `` unlawfully over populated neighborhoods , killing and wounding civilians and damaging civilian structures , including a school , a market , a humanitarian aid warehouse and a hospital. `` `` First , the repeated use of air-burst white phosphorus in populated areas until the last days of the operation reveals a pattern or policy of conduct rather than incidental or accidental usage . Second , the IDF was well aware of the effects of white phosphorus and the dangers it poses to civilians . Third , the IDF failed to use safer available alternatives for smokescreens , '' the report said . A medical report prepared during the recent hostilities by the Israeli Health Ministry said that white phosphorus `` can cause serious injury and death when it comes into contact with the skin , is inhaled or is swallowed . '' The report said that the IDF could have used a non-lethal smoke shells produced by an Israeli company if it wanted to provide a `` smokescreen '' for its troops . Israel launched the offensive in late December to take on militants from Hamas , who had been shelling southern Israeli communities for months from Gaza . The offensive , called Operation Cast Lead , was launched December 27 and ended January 17 with a cease-fire . Of the 1,453 people estimated killed in the conflict , 1,440 were Palestinian , including 431 children and 114 women , a U.N. report recently said . The 13 Israelis killed included three civilians and six soldiers killed by Hamas , and four soldiers killed by friendly fire , it said . HRW also said it found no evidence that the Hamas militants Israel was targeting in Gaza were using human shields `` in the vicinity at the time of the attacks . '' Israel has said Hamas militants used civilians as human shields and fought from civilian locations , HRW points out . `` In some areas Palestinian fighters appear to have been present , but this does not justify the indiscriminate use of white phosphorus in a populated area . ''
Israel 's use of artillery shells over during Gaza offensive ` ` indiscriminate '' Human Rights Watch calls shelling ` ` ##s of fire ' '' Israel says phosphorus shells cause an ` ` intense and persistent burn ''