U.N. Secretary-General Ban Ki-moon cast doubt on Thursday on the credibility of Israeli and Palestinian investigations into U.N. allegations of war crimes during the 2008-2009 war in the Gaza Strip.

In a cautiously worded message to the U.N. General Assembly, Ban acknowledged Israel and the Palestinian Authority were looking into the behavior of Israeli soldiers and Palestinian militants as demanded by a resolution the 192-nation assembly approved in November.

But Ban withheld judgment on whether the probes were "independent, credible and in conformity with international standards."

"No determination can be made on the implementation of the resolution by the parties concerned," Ban said in the letter that accompanied the documents given to him by the Israelis and the Palestinian Authority about their investigations.

One senior Western diplomat described Ban's letter as "deadpan and procedural." It was not immediately clear what, if anything, the General Assembly would do in response.

More than 1,400 Palestinians and 13 Israelis died after Israel launched Operation Cast Lead against Gaza to try to end rocket fire against its cities. Critics charged that Israel used excessive and indiscriminate firepower but Israel blamed the militants for hiding among civilians.

The General Assembly resolution was a response to a U.N. report issued last September by an investigative panel headed by South African jurist Richard Goldstone.

The Goldstone report said the Israeli army and Palestinian militants committed war crimes during the conflict from late December 2008 to mid-January 2009 but focused more on Israel.

It also said that if Israel and the Palestinians failed to carry out credible investigations, the matter should be referred to the International Criminal Court in The Hague.

Both the Jewish state and the Islamist group Hamas, which controls the Gaza Strip, have rejected the suggestion they might have been responsible for war crimes.

FURY AND COOPERATION

"I have called upon all of the parties to carry out credible domestic investigations," Ban said in the letter. "I hope that such steps will be taken wherever there are credible allegations of human rights abuses."

Last week, Ban received a document from Israel defending its handling of complaints over its conduct in the Gaza war.

The Palestinian Authority, which has no control over Gaza and played no direct role in that conflict, gave the United Nations details of a commission of inquiry it had set up, along with preliminary findings.

Hamas said it gave the United Nations a response to the Goldstone report rejecting the charges against its fighters. The Hamas response was not included in Ban's message to the General Assembly.

Israel had refused to cooperate with Goldstone and angrily rejected his findings. Last week, Israeli Defense Minister Ehud Barak called the report "distorted, biased and unbalanced."

But after the General Assembly called on Israel and the Palestinians in November to investigate Goldstone's charges and asked Ban to report back within three months, Israel decided it would provide the U.N. chief with information.

Despite its fury at Goldstone's report, Israel last month paid $10.5 million to the United Nations for damage to U.N. property during the Gaza war. (Editing by John O'Callaghan)