Jerusalem ( CNN ) -- An international human rights organization on Sunday faulted Israel 's investigation into alleged war crimes last year in Gaza . Israel has not demonstrated that it will conduct thorough and objective investigations , Human Rights Watch said in a statement . `` An independent investigation is crucial to understand why so many civilians died and to bring justice for the victims of unlawful attacks , '' said Joe Stork , deputy Middle East director for the New York-based organization . In September , the United Nations Human Rights Council released a report by noted South African jurist Richard Goldstone . The report concluded that both sides committed war crimes during the conflict , which killed about 1,400 Palestinians and 13 Israelis . But U.N. chief Ban Ki-moon said last week that the world body has not made a determination on whether both sides have done enough to investigate allegations they committed war crimes during the three-week conflict , which began at the end of December 2008 . In a report , Ban outlines steps Israelis and Palestinians have taken to fulfill a U.N. demand for credible and transparent inquiries into civilian casualties . However , he concludes , `` As such , no determination can be made on the implementation of the resolution by the parties concerned . '' Israel handed Ban a response outlining the steps the nation has taken to investigate charges of wrongdoing by its military during the course of the offensive in Gaza , which was aimed at stopping militant rocket fire into Israel . The Israeli military has `` launched investigations into 150 separate incidents , including 36 criminal investigations opened thus far , '' according to the report . For its part , the Palestinian Authority said it had created a commission to look into various charges of abuses , but made clear that it did not view the potential wrongdoing on the Palestinian side as seriously as that allegedly committed by the Israeli military . `` There is absolutely no symmetry or proportionality between the occupying power and the occupied people '' wrote Riyad Mansour , Palestinian ambassador to the United Nations . In Gaza , the ruling Hamas movement released a summary of the steps taken to investigate wrongdoing , saying it had prevented militants from targeting civilians . But the rights organization dismissed the conclusion as `` factually wrong . '' Human Rights Watch said it is still reviewing a full Hamas report . `` Hamas can spin the story and deny the evidence , but hundreds of rockets rained down on civilian areas in Israel where no military installations were located , '' Stork said . `` Hamas leaders at the time indicated they were intending to harm civilians . '' CNN 's Kevin Flower contributed to this report .
Human Rights Watch says Israel has not shown it will conduct objective probe . Group also faults Hamas report on Gaza conflict , which it is still reviewing . Both sides are reporting on alleged war crimes during Gaza conflict a year ago . About 1,400 Palestinians and 13 Israelis were killed during the Israeli incursion .