AMSTERDAM, Feb 8 (Aaron Gray-Block/Reuters) - Palestinian Authority officials will present more arguments in March urging the International Criminal Court to investigate possible war crimes during the Israeli offensive in Palestinian-ruled Gaze, the court's chief prosecutor said.

The ICC prosecutor launched a preliminary examination in 2009 to establish whether war crimes were committed by either side in Gaza. The Palestinian Authority has recognized the ICC's jurisdiction in a bid to allow a court investigation.

They will be back in March with more legal arguments, so we are letting them come here before making any decision, ICC chief prosecutor Luis Moreno-Ocampo said in an interview at his office in The Hague. It is a very complex decision.

About 1,400 Palestinians, including hundreds of civilians, were killed in the three-week Israeli offensive launched on Dec. 27, 2008 and while a September U.N. report blasted both sides in the conflict, it was harsher in its judgement towards Israel.

The ICC can investigate alleged war crimes in a state party's territory if the U.N. Security Council -- where the United States, Israel's main backer, has veto power -- refers a situation to the court or if a non-state party voluntarily accepts its jurisdiction.

QUESTION OF JURISDICTION

Israel, however, has not signed the Rome Statute creating the court. It also argues that Palestine is not a state and so the ICC has no jurisdiction to start a probe in the Palestinian territories.

But the Palestinian Authority says it is a state, pointing to the Oslo Accords signed in 1993 between Israel and the Palestinian Liberation Organisation on Palestinian interim self-government.

The prosecutor has received submissions arguing that Palestinians accepted not to exercise criminal jurisdiction over Israelis on their territories.

They are now evaluating how to conduct a national investigation and if, at the end of the day, they do the investigation, that is preferable. Moreno-Ocampo said.

Israel and the Palestinians were urged by U.N. investigator Richard Goldstone in September to conduct credible inquiries into possible war crimes committed by their forces in Gaza.