GAZA CITY (AFP) - A UN human rights mission listened to testimony about the suffering of children in the Gaza Strip on Monday before wrapping up two days of public hearings into alleged Israeli war crimes. Around 20 percent of children in Gaza suffer from post-traumatic stress syndrome brought on by witnessing violent acts, child psychologist Dr Iyad Sarraj told the panel. The amount of killing and blood that they have seen or that their relatives have suffered from... its a huge amount, and this leads to negative psychological feelings, to radicalism and a cycle of violence, he said. More than half of Gazas population of 1.5 million is under 18 years of age. The public hearings are part of the UN Human Rights Councils investigation of the 22-day Israeli offensive launched in late December that killed about 1,400 Palestinians and 13 Israelis. The Red Cross meanwhile said in a new report that six months after the devastating offensive Palestinians in the impoverished coastal territory are unable to rebuild their lives and are sliding ever deeper into despair. Israeli and Egyptian sanctions imposed on Gaza after Hamas seized power in June 2007 have crippled reconstruction efforts and caused widespread misery, according to the study by the International Committee of the Red Cross (ICRC). The poorest residents in particular have exhausted their coping mechanisms and often have to sell off their belongings to be able to buy enough to eat, said Antoine Grand, head of the ICRC sub-delegation in Gaza. Worst affected are the children, who make up more than half of Gazas population, he added. The report said that seriously ill patients were not getting the treatment they needed and thousands of Gazans whose homes were destroyed during Israels 22-day military operation at the turn of the new year were still without shelter. The ICRC report said in the wake of the Israeli offensive essential water and sanitation infrastructure remain largely insufficient and that the equivalent of 28 Olympic-size swimming pools of basically untreated sewage is daily pumped into the Mediterranean Sea. Some 4.5 billion dollars pledged by donor countries to rebuild Gaza is of little use if building supplies cannot get past the Israeli blockade, the ICRC said, calling for the lifting of restrictions on the movement of people and goods. Israel has the right to protect its population against attacks, said Grand. But does that mean that 1.5 million people in Gaza do not have the right to live a normal life? The Geneva-based humanitarian organisation said Gaza urgently needed to import medical equipment and building supplies including cement and steel, and its farmers needed access to their land in the buffer zone and its fishermen should be allowed back into deeper waters. The ICRC also called for political authorities and the armed groups in Gaza to take the necessary steps to help the civilians. Humanitarian action can be no substitute for the credible political steps that are needed to bring about the changes the population of Gaza needs, the ICRC said. The UN mission in Gaza is headed by Richard Goldstone, a South African judge who previously served as chief prosecutor for international criminal tribunals for the former Yugoslavia and Rwanda. On Sunday, the mission heard a wheelchair-bound man describe how an Israeli shell slammed into his home, killing 11 of his relatives and cutting off his legs. Another man described a strike on a mosque that killed 17 people. The group was expected to look into several allegations of human rights violations that emerged in the aftermath of the assault, which Israel said was aimed at stemming Palestinian rocket fire from the Hamas-ruled enclave. The UN Human Rights Council has over the last months and years totally discredited itself as a serious vehicle for advancing human rights. The 47-member council voted by a large majority in January to probe accusations of grave human rights violations by Israel, but the team was later given a broader mandate to deal with all violations during the war. Israel has insisted it made every effort to spare civilians, including dropping thousands of fliers warning residents to flee ahead of strikes. It has also said that Palestinian fighters and rocket launchers operated in crowded residential areas, a charge also lodged by human rights groups against the Hamas movement ruling Gaza. The group plans to hold similar hearings in Geneva in which they will interview witnesses and experts on alleged violations in Israel and the occupied West Bank, and to issue a final report by September 12. The international community has pledged billions of dollars in aid to rebuild the territory, but reconstruction efforts remain paralysed by the closures, which prevent the import of virtually all building materials.