Israel has offered time-limited safe routes to more than a million Palestinians ordered to leave northern Gaza as the military carried out "localised raids" ahead of an expected ground assault.
The mass exodus came despite warnings from the United Nations and aid groups such a forced evacuation would have devastating humanitarian consequences, with hospital patients and others unable to move.
Israel has now extended a deadline for people to leave, allowing the safe movement of Gazans on two main roads south between 10am and 4pm local time (8am and 2pm UK time).
As families in cars, lorries and donkey carts packed with their possessions headed south from Gaza City, Israeli airstrikes continued in the besieged territory.
Hamas said 70 people, mostly women and children, had been killed in an attack on a fleeing convoy.
Sky News has seen footage that appears to show the truck both before and in the aftermath of the strike.
It was not immediately clear who the target of the airstrikes was, or whether militants were among the passengers.
Meanwhile, the Israeli Defence Force (IDF) said its troops conducted raids into Gaza to battle insurgents and hunt for more than 120 civilians kidnapped in last weekend's shock assault by militants on southern Israel.
It is the first time Israel has stated ground troops have been operating inside the strip
