Israel is set to soon halt or slow humanitarian aid to parts of northern Gaza as it ramps up its military offensive against Hamas, an official said on Saturday, a day after Gaza City was declared a combat zone.

The move is likely to invite further criticism of the Israeli government, as frustration grows both domestically and internationally over the dire conditions faced by Palestinians and the remaining hostages in Gaza after nearly 23 months of conflict.

The official, who spoke on condition of anonymity as they were not authorised to speak to the media, told The Associated Press that Israel will stop airdrops over Gaza City in the coming days and reduce the number of aid trucks arriving, as it prepares to evacuate hundreds of thousands of people south.