The IDF said Wednesday that it is investigating reports that ammunition containing elements of phosphorus were used during Operation Cast Lead in the Gaza Strip, in response to a Human Rights Watch report alleging such use. The rights group claimed Israel fired these shells repeatedly over crowded neighborhoods, and that senior IDF commanders should be held accountable. The army's investigation, according to the report, was looking into "the use of ammunition containing elements of phosphorous, including, amongst others, the 155mm smoke shells which were referred to in the Human Rights Watch report." The army noted that such ammunition "disperses in the atmosphere and creates an effective smoke screen," and that "it is used by many western armies" The rights group's report claimed safer smoke shells were available, and that civilians suffered and died needlessly. The IDF, however, specified that smoke shells are "not an incendiary weapon," citing the third protocol of the Convention on Certain Conventional Weapons. The IDF statement said that the investigation was close to its conclusion, and that its results would be publicized shortly.