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 IDF has told residents: For your safety, evacuate immediately.
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. If I knew [somewhere to go], I would have left [by now] and taken my family and my children, said Hanaa, a mother of three.
The message from the Israel Defense Forces (IDF) was clear as they distributed leaflets warning of the upcoming military operations. The deteriorating conditions for civilians are evident, with UN agencies raising alarms about the humanitarian crisis stemming from the military mobilization.
As the situation evolves, the broader implications of the Israeli offensive and the humanitarian response will remain critical issues.
