New Israeli bombardment comes on the verge of a U.S. deadline for Israel to ramp up humanitarian aid allowed into Gaza or risk restrictions on military aid.

Residents said Israeli forces besieged shelters housing displaced families and the remaining population, which some estimated at a few thousand, ordering them to head south through a checkpoint separating two towns and a refugee camp in the north from Gaza City.

Four Israeli soldiers have been killed in the north of the Gaza Strip, the Israeli military reported on Tuesday. The dead soldiers were non-commissioned officers aged 20 and 21, it said. Israeli media reports said they were killed when an antitank weapon fired by Palestinian forces struck a building where they were sheltering in the Jabalia refugee camp to the north of Gaza City.