Geneva  - The recent Israeli operation in the Gaza Strip was illegal and included violations of human rights and possible crimes against humanity, the United Nations' expert on the Palestinian territories said Monday.

"To the extent that the combat zone was so densely populated by civilians, it meant that, with the types of weaponry relied upon, there was no lawful way to carry out the Israeli military operations," said Richard Falk, addressing the Human Rights Council in Geneva.

He said the death ratio of 1,434 Palestinians to 13 Israelis was "a basis for challenging the legality" of the operation against an "essentially defenseless society."

Falk also focused on what he said was Israel's effective denial of allowing Palestinians in Gaza to flee the combat zone.

"Such a war policy should be treated as a distinct and new crime against humanity," the special rapporteur said.

Falk reiterated calls by other UN officials for an investigation into war crimes allegations regarding acts by Israel and Hamas, the Islamic movement which rules Gaza.

He issued a similar call in a report released last week and said that if an enquiry found that individuals could be criminally responsible, a next step would be the setting up of a UN-sponsored "ad hoc criminal tribunal for occupied Gaza."

In Israel, the Chief of Staff Gaby Ashkenazi said in the morning that Israeli soldiers did not systematically and wilfully kill Palestinian civilians "in cold blood." He noted there were ongoing investigations and if "single cases" emerged, these would be brought to justice.

Testimonies of Israeli soldiers published over the weekend by a newspaper in Tel Aviv, painted a picture of lax rules of engagement that allowed for the killing of Palestinian civilians during Israel's 22-day offensive in the Gaza Strip.

Alongside Falk, Olivier de Schutter, the special rapporteur on the right to food, delivered a joint report of nine UN experts, which also condemned the military operation and the ongoing blockade on the coastal territory.

De Schutter also said the experts were concerned by the use of human shields by both parties, allegations that Hamas executed Palestinian civilians during the Israeli operation and "questionable use" of certain weapons during the fighting.

Both experts also called Palestinian rocket fire against Israeli civilians unlawful.

Aharon Leshno-Yaar, the Israeli ambassador to the UN in Geneva, said the joint report "downplays terrorists threats we face" and noted a recent attempt to blow up a car bomb in shopping mall in northern Israel.

He said there was an established double-standard against Israel.

Israel, he said, tried to ensure that its operations were "conducted in accordance with the requirements of international humanitarian law."

Falk, a controversial American-Jewish jurist, has been deemed by Israel to be "unwelcome" and was denied entry to the country last year. (dpa)