GAZA CITY, Gaza Strip — The Israeli military on Thursday staged its deepest strike into Gaza City, striking the headquarters of the United Nations and sending thousands of panicked residents fleeing their homes.
Black smoke billowed over Gaza City after the Israeli shell struck the U.N. compound, setting fire to the central warehouse for the U.N.'s refugeee agency and injurying three workers.
The attack drew immediate protest from United Nations Secretary-General Ban Ki-Moon, who was preparing to meet with Israeli Foreign Minister Tzipi Livni when he got word of the strike.
Ban voiced his "outrage" over the shelling and said that Israeli Defense Minister Ehud Barak had personally apologized to him for the attack.
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"The defense minister said to me it was a grave mistake and he took it very seriously," Ban told reporters in Tel Aviv before meeting with Livni to discuss United Nations efforts to bring the fighting to an immediate end.
Witnesses said another strike hit a Red Crescent hospital, setting the administration building ablaze and trapping dozens of workers inside. Another strike hit several high-rise buildings, including one housing the Thompson-Reuters news offices.
The Associated Press reported that its office in a different building was hit by gunfire.
Middle East diplomats converged on Cairo where negotiators are trying to broker a cease-fire. They included an Israeli, Amos Gilad, who arrived in Cairo on Thursday.
Hamas is under increasing pressure – both from the Israeli military in Gaza and Arab diplomats in Egypt – to accept an Egyptian truce proposal. While Hamas leaders say they back the Egyptian plan in principle, they have not yet agreed to accept the details.
Egypt has proposed a temporary halt to the fighting to allow mediators to draw up a longer-term cease-fire deal.
But crafting a stable plan could prove difficult.
Israel has said it won't end the military operation until Hamas halts persistent rocket fire aimed at southern Israeli cities and world leaders ensure that the hard-line Islamist forces running Gaza are not able to smuggle in more weapons through tunnels under the Gaza-Egypt border.
Hamas has refused to concede defeat and has vowed to keep fighting until Israel agrees to allow a normal flow of critical aid and supplies to reach Gaza.
Egyptian, Israeli and Hamas leaders have all suggested in recent days that a deal could be secured, though the parties have yet to agree on the details.
More Palestinians have been killed in Israel's 20-day offensive in Hamas-controlled Gaza than in any single year this decade. Some 40 percent of the more than 1,000 dead are women and children, according to Palestinian medical officials.
More than 4,500 more people reportedly have been wounded as Israeli forces have taken aim at densely populated civilian areas that military officials say Hamas fighters use as cover. On the Israeli side, 13 people have died, 10 of them soldiers.
As Israeli soldiers clamped down on Gaza City, thousands of residents fled their homes looking for safety. Residents were seen running from their homes in nightgowns and pajamas.
In response to the strike on media offices in Gaza City, the Foreign Press Association in Israel denounced Israel’s "unconscionable breaches" and urged members not to distribute or broadcast photos or video given to them by the Israeli military until there was a formal apology.
Since early November, Israel has imposed a near-blanket ban on international reporters entering Gaza, despite a decision by Israel's highest court to allow reporters into Gaza during the fighting.
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