Israel has warned all residents of Gaza City to leave immediately in anticipation of a huge ground offensive.
The military's Arabic spokesman told as many as one million Palestinians living in Gaza's biggest urban centre to evacuate southwards. 'Remaining in the area is extremely dangerous,' he said.
On Monday, Israeli Prime Minister Benjamin Netanyahu said air strikes that had destroyed high-rise buildings in Gaza City in recent days were 'only the beginning of the main, intensive operation' to capture what he has described as Hamas's last important stronghold.
Hamas said his remarks amounted to a 'public demonstration of a fully-fledged crime of forced displacement'.
Israel's plan to conquer Gaza City has also brought international criticism.
The UN has warned an intensification of the offensive on an area where a famine has already been declared will push civilians into an 'even deeper catastrophe'.
The message from the Israel Defense Forces (IDF) - both in leaflets dropped over Gaza City, and posted on social media by its Arabic spokesman Col Avichay Adraee - was unequivocal. 'To all residents and those present in Gaza City and all its areas, from the Old City and the Tuffah area in the east to the sea in the west: The IDF is determined to defeat Hamas and will operate in Gaza City with great determination, as it has throughout the Gaza Strip.'
'For your safety, evacuate immediately,' it added.
Photographs showed a stream of people moving south along the coastal road from Gaza City on foot, on donkey carts, and in vehicles on Tuesday, but there was no sign of a mass exodus.
The UN has also warned that the tent camps there are already overcrowded and local hospitals are operating at several times their capacity.
Since UN-backed global food security experts confirmed a famine in Gaza City on 22 August, Gaza's Hamas-run health ministry has reported that at least 121 people have died from starvation and malnutrition across the territory.
