GAZA CITY, Gaza Strip -- Palestinian President Mahmoud Abbas is seeking written pledges of support from all political factions, including rival Hamas, before making any attempt to press for possible war crimes charges against Israel, senior officials said Thursday.
Abbas hesitated in the past because such a step would transform his relations with Israel from tense to openly hostile and could put him on a collision course with the United States.
But with nearly 1,400 Palestinians killed in Israel-Hamas fighting in Gaza in the past 24 days, according to health officials, Abbas is under growing domestic pressure to turn to the International Criminal Court to try to make a case against Israel.
Israeli officials have said Israel is acting in self-defense by targeting Hamas' military arsenal and rocket-launching sites and have accused Hamas of using Gaza civilians as human shields.
Earlier Thursday, the U.N.'s top human rights official accused both Israel and Hamas of committing war crimes in the current Gaza fighting.
U.N. High Commissioner for Human Rights Navi Pillay said Hamas is committing war crimes by firing rockets from heavily populated areas and storing them in schools and hospitals.
She said Israel has defied international law in Gaza by attacking civilian areas with schools, hospitals, homes and U.N. facilities.
"None of this appears to me to be accidental," Pillay said of Israel at a news conference in Geneva to mark the end of her six-year term. "They appear to be defying -- deliberate defiance of -- obligations that international law imposes on Israel."
She also criticized Israel's strikes on Gaza's power plant, sewer systems and water wells as part of a similar pattern of destruction during the 2009 Gaza war.
Israeli Foreign Ministry spokesman Yigal Palmor declined comment.
Hamas has portrayed its rocket fire on Israel as resistance to Israeli occupation of Palestinian territories.
With the Palestinian casualties in Gaza mounting, leaders of political factions in the West Bank have repeatedly urged Abbas to seek Palestinian accession to the International Criminal Court.
"We have been pressing him for a long time," independent legislator Mustafa Barghouti said Thursday.
At a meeting with political leaders on Tuesday, Abbas asked participants to sign a declaration of support for such a move, said Barghouti, adding that everyone signed.
The final decision, on when to seek accession, would still be up to Abbas, according to other participants who spoke on condition of anonymity because there were discussing internal deliberation.
They said Abbas also told them he would not move forward without written consent from Hamas and Islamic Jihad because they could expose themselves to possible war crimes charges.
Abbas' Fatah movement wrote on its official Facebook page that Abbas is seeking broad consensus, in part because of the potential repercussions for Hamas.
"Regarding the question a large number of brothers and sisters, 'why dont you go to the International Criminal Court,' the leadership of the State of Palestine will sign the Rome Statute all the way to the International Criminal Court after ... the approval of all the Palestinian factions, including Fatah and Hamas and Islamic Jihad, because this option is a double-edged sword," Fatah wrote.
Hamas officials in Gaza were not immediately available for comment.