Photo: Right: Head of the UN Fact Finding Mission on the Gaza Conflict, former South African judge Richard Goldstone.

Israeli forces committed war crimes and possibly crimes against humanity during their assault on the Gaza Strip eight months ago, the head of a UN fact-finding rights mission said Tuesday.

Richard Goldstone told reporters that his four-member probe panel "concluded that actions amounting to war crimes and possibly in some respect crimes against humanity were commited by the Israel Defense Forces."

The report said Israel deliberately attacked civilians, failed to take precautions to minimize loss of civilian life and cited strong evidence Israeli forces committed "grave breaches" of the Geneva Convention.

The firing of white phosphorous shells and the use of high explosive artillery shells were listed as "violations of humanitarian law."

"There were numerous instances of deliberate attacks on civilians and civilian objects in violation of the fundamental international humanitarian law principle of distinction, resulting in deaths and serious injuries," it added.

It said there was "strong evidence that Israeli forces committed grave breaches of the Fourth Geneva Convention in Gaza, including willful killing, torture or inhumane treatment, willfully causing great suffering or serious injury to body or health, or extensive destruction of property.

"The Israeli operations were carefully planned in all their phases as a deliberately disproportionate attack designed to punish, humiliate and terrorize a civilian population," it said.

In a 575-page report, Goldstone and three other investigators also found evidence "that Palestinian armed groups committed war crimes, as well as possibly crimes against humanity."

Goldstone said the probe, which included interviews as well as a review of documents, photos and 30 videos, was completed Tuesday morning, just hours before the hastily called news conference.

"There should be no impunity for international crimes that are committed," said Goldstone, a veteran war crimes investigator who has served as chief prosecutor for the U.N. criminal tribunals for the former Yugoslavia and Rwanda. "It's very important that justice should be done."

The report said that Israel's attacks in the Zeitoun neighborhood of Gaza City, including the shelling of a house where soldiers had forced Palestinian civilians to assemble, amounted to war crimes.

It found seven incidents in which civilians were shot while leaving their homes trying to run for safety, waving white flags and sometimes even following Israeli instructions, as well as the targeting of a mosque at prayer time, killing 15 people, were also war crimes.

Investigators found no evidence the mosque was used to store weapons or for any military activity by Palestinian armed groups, but said they were unable to look more broadly at Israel's allegation that the mosques were used generally by Palestinian groups for storing weapons.

A "direct and intentional attack" on the Al Quds Hospital and an adjacent ambulance depot in Gaza City "may constitute war crimes," the report said.

Several Palestinians told the mission they were used as human shields by the Israeli forces, the report said, noting the case of Majdi Abd Rabbo, a 39-year-old intelligence officer of the Palestinian authority who was forced to walk ahead of the troops as they searched his and his neighbor's house. Rabbo was forced to undress down to his underwear in front of the soldiers and his sons had to strip naked, the report said.