The IDF unlawfully fired white phosphorus shells over densely populated areas of the Gaza Strip during its recent offensive, needlessly killing and injuring civilians, Human Rights Watch said on Wednesday.
Citing Israel's use of white phosphorus as evidence of war crimes, the group said the army knew the munitions threatened the civilian population but "deliberately or recklessly" continued to use them until the final days of the Dec. 27-Jan. 18 operation "in violation of the laws of war."
The Human Rights Watch report, one of several issued by international organizations to sharply criticize Israel's conduct, called on senior military commanders to be held to account, and urged the United States, which supplied the shells, to launch its own investigation.
The Israeli army announced after the war that it would conduct an internal probe.
"We're checking the claims we received from different NGOs ... of using white phosphorus shells in illegal ways, according to those claims, and this is what we're investigating," an Israeli military spokeswoman, Major Avital Leibovich, said.
White phosphorus ignites on contact with oxygen and continues burning at up to 1,500 degrees Fahrenheit (816 degrees Celsius) until none is left or the oxygen supply is cut. It is often used to produce smoke screens, but can also be used as a weapon, producing extreme burns if it makes contact with skin.
When used in open areas, white phosphorus munitions are permissible under international law.
But Human Rights Watch said Israel "unlawfully" fired them over populated neighborhoods, killing and wounding civilians and damaging civilian structures, including a school, a market, a humanitarian aid warehouse and a hospital.
"In Gaza, the Israeli military didn't just use white phosphorus in open areas as a screen for its troops," said senior Human Rights Watch researcher Fred Abrahams. "It fired white phosphorus repeatedly over densely populated areas, even when its troops weren't in the area and safer smoke shells were available. As a result, civilians needlessly suffered and died."
The group gave no precise casualty figures, citing the difficulty of determining in every case which burn injuries were caused by white phosphorous.