( CNN ) -- More than 1,300 Palestinians died and about 5,400 others were wounded during Israel 's three-week offensive in Gaza , the Web site of the Palestinian Authority 's Central Bureau of Statistics said Monday . A Palestinian man Monday prays in the rubble of his home , destroyed during Israel 's offensive in Gaza . Louay Shabana , head of the agency , said more than 22,000 buildings were damaged or destroyed . Shabana put the economic destruction at more than $ 1.9 billion . The fighting largely stopped Sunday with a cease-fire . Israel has said 13 of its citizens -- including 10 soldiers -- were killed during the offensive , which started December 27 . Israel said its offensive was aimed at stopping Hamas militants from firing rockets into southern Israel . Gaza is in need of humanitarian , economic , sanitary and social help as a result of the Israeli attacks , Shabana said . The attacks destroyed public sector and private buildings in Gaza , affecting even the United Nations Relief and Works Agency 's facilities and halting economic and social services , the statistics agency said . Watch Palestinians recover bodies from rubble » . Gaza 's gross domestic product was slashed by 85 percent during the 22 days of war , and it could take a year for the economy to recover , the agency said in a preliminary report . About 80 percent of crops in Gaza were destroyed , according to the agency . `` The pervasive sense here among the population is one of overwhelming grief , so many families have been destroyed in so many ways , '' said John Ging , the top United Nations official in Gaza . Ging , UNRWA 's Gaza director of operations , said the bill could reach `` billions of dollars . '' Among the dead were 159 children , two of whom died in an UNRWA school that was shelled Saturday , Ging said . Gaza 's main border crossings , which Israel often closed in response to Hamas rocket attacks , were open Monday . Infrastructure repairs were being made , but 400,000 people still had no water , according to Ging . Streets in some northern Gaza towns were flooded with sewage , and about 50 U.N. facilities were damaged , he said . More than 170 supply trucks crossed into Gaza on Monday , less than a third of the daily number that crossed in 2005 , said John Holmes , U.N. under-secretary-general for humanitarian affairs and emergency relief coordinator . Israel tried to avoid civilian casualties in Gaza , a senior Israel Defense Forces officer said in a posting Monday on the IDF Web site . `` This was not a war against the Palestinians , '' he said . `` It was an operation of self-defense against Hamas and related terror organizations . Unfortunately , this task was made extremely difficult by Hamas , as they made the choice to use civilians as human shields . '' Israel began the offensive in response to rocket fire by Hamas militants after showing eight years of restraint , the officer said . The operation 's goal , he said , `` was to improve the security situation in southern Israel , and to facilitate peaceful living for the Israeli civilians living there . '' `` We asked ourselves how to accomplish this , and the answer was to hit Hamas hard -- to strike the tunnels , the terrorists themselves , and all of their assets -- in order to prevent them from committing war crimes by firing rockets that target our civilian population , '' the officer said . He said seven rockets have been fired from Gaza into Israel since Sunday 's cease-fire declaration . `` We want to give this cease-fire a chance , but if Hamas chooses not to , we will utilize all of our means , '' he said .
Israeli offensive caused $ 1.9 billion in economic destruction in Gaza , official says . It could take a year for Gaza 's economy to recover , Palestinian agency says . Comment: