Amnesty International on Friday asked Israel to disclose the weapons and munitions its forces used during the three week military offensive in Gaza which claimed over 1300 lives.
"We now know that white phosphorous munitions were used in built-up civilian areas, although the Israeli authorities previously denied this," said Donatella Rovera, who is heading an Amnesty International investigation team in Gaza.
"Now we have irrefutable evidence of the use of this weapon, but the doctors who treated the first casualties did not know what had caused their injuries."
Other victims of the conflict have wounds which doctors say they are finding hard to treat because of uncertainty about the nature of the munitions which caused them.
"Doctors tell us they are encountering new and unexplained patterns of injury among some of the Palestinians injured in Israeli military attacks," said Rovera.
"Some victims of Israeli air strikes were brought in with charred and sharply severed limbs and doctors treating them need to know what weapons were used."
Subhi Skeik, head of the Surgical Department at al-Shifa Hospital in Gaza, told Amnesty International delegates: "We have many cases of amputations and vascular reconstructions where patients would be expected to recover in the normal way. But to our surprise many of them died an hour or two after operation. It is dramatic."
"It is vital and urgent that the Israeli authorities disclose all relevant information including what weapons and munitions they used," said Rovera.
"More lives must not be lost because doctors do not know what caused their patients' injuries and what medical complications may occur. They have to be fully informed so that they can provide life-saving care," Rovera added.