Online Desk: Israel’s military on Friday directed the evacuation of northern Gaza, a region that is home to 1.1 people — about half of the territory’s population — within 24 hours, a UN spokesman said. This could signal an impending ground offensive, though the Israeli military has not yet confirmed such an appeal. On Thursday it said that while it was preparing, a decision has not yet been made.

The order, delivered to the UN, comes as Israel presses an offensive against Hamas militants. UN spokesman Stéphane Dujarric called the order “impossible” without “devastating humanitarian consequences.” Earlier, the Israeli military pulverized the Gaza Strip with airstrikes, prepared for a possible ground invasion and said its complete siege of the territory — which has left Palestinians desperate for food, fuel and medicine — would remain in place until Hamas militants free some 150 hostages taken during a grisly weekend incursion, AP reports.

A visit by Secretary of State Antony Blinken, along with shipments of US weapons, offered a powerful green light to Israel to drive ahead with its retaliation in Gaza after Hamas’ deadly attack on civilians and soldiers, even as international aid groups warned of a worsening humanitarian crisis. Israel has halted deliveries of basic necessities and electricity to Gaza’s 2.3 million people and prevented entry of supplies from Egypt. “Not a single electricity switch will be flipped on, not a single faucet will be turned on and not a single fuel truck will enter until the Israeli hostages are returned home,” Israeli Energy Minister Israel Katz said on social media.

Lt Col Richard Hecht, an Israeli military spokesman, told reporters Thursday that forces “are preparing for a ground maneuver” should political leaders order one. A ground offensive in Gaza, which is ruled by Hamas and where the population is densely packed into a sliver of land only 40 kilometers (25 miles) long, would likely bring even higher casualties on both sides in brutal house-to-house fighting.

Hamas’ assault Saturday and smaller attacks since have killed more than 1,300 people in Israel, including 247 soldiers — a toll unseen in Israel for decades — and the ensuing Israeli bombardment has killed more than 1,530 people in Gaza, according to authorities on both sides. Israel says roughly 1,500 Hamas militants were killed inside Israel, and that hundreds of the dead in Gaza are Hamas members. Thousands have been wounded on both sides.

As Israel pounds Gaza from the air, Hamas militants have fired thousands of rockets into Israel. Amid concerns that the fighting could spread in the region, Syrian state media reported that Israeli airstrikes on Thursday put two Syrian international airports out of service. The relentless barrage on Gaza — which the military said has so far involved 6,000 munitions — left Palestinians running through streets, carrying their belongings and looking for safety. A strike Thursday afternoon in the Jabaliya refugee camp took down a residential building on families sheltering inside, killing at least 45 people, Gaza’s Interior Ministry said. At least 23 of the dead were under the age of 18, including a month-old child, according to a list of the casualties.