AFP, Washington :The United States confirmed it had restocked Israel’s supplies of ammunition, hours after finally sharpening its tone to condemn an attack on a United Nations school in Gaza.But while both the White House and the State Department condemned the shelling of the UN-run school in the Jabaliya refugee camp in northern Gaza in which at least 16 Palestinians were killed, neither would assign blame to staunch US ally Israel.”Obviously nothing justifies the killing of innocent civilians seeking shelter in a UN facility,” deputy State Department spokeswoman Marie Harf acknowledged, in some of the toughest US comments since the start of the 23-day fighting in the Gaza Strip. “Innocent Palestinians seeking refuge in these schools should not have shells dropped on them, should not come under attack.” The UN agency for Palestinian refugees UNRWA said Israeli forces had hit the school, which had been sheltering some 3,300 Gazans. But despite heated exchanges with reporters, Harf stressed that “we don’t know for certain who shelled this school, we need to get all the facts.”National Security Council spokeswoman Bernadette Meehan also condemned “those responsible for hiding weapons in United Nations facilities in Gaza” and warned of rising fears that thousands of Palestinians who have been told by Israel to leave their homes increasingly had nowhere to go in the blockaded narrow coastal strip. US officials also warned that patience with “crazy” Israeli criticism of would-be-peacemaker John Kerry had snapped.The Pentagon confirmed the Israeli military had requested additional ammunition to restock its dwindling supplies on July 20, with the US Defense Department approving the sale just three days later. “The United States is committed to the security of Israel, and it is vital to US national interests to assist Israel to develop and maintain a strong and ready self-defense capability,” Pentagon spokesman Rear Admiral John Kirby said in a statement.