UPDATE: Hamas will start a new unofficial truce at 8pm local time, according to Palestinian sources close to the ceasefire negotiations in Cairo.
Early reports from Egypt indicate that only minor disagreements remain between the two sides.
The previous three-day Gaza ceasefire expired at 8am local time as talks broke down amid rocket fire from Hamas and retaliatory air strikes by Israel.
Air raid sirens were heard in the coastal city of Ashkelon and in the Eshkol area when Hamas launched a fresh onslaught of rockets against southern Israel. One rocket was intercepted over Ashkelon while others fell in open fields.
The Israeli military was ordered to hold its fire for over two hours before Prime Minister Netanyahu instructed the air force to respond with a fresh wave of bombing.
Al Jazeera reported that at least three air strikes have hit different parts of the Gaza Strip on Friday morning.
It is still hoped that the renewed violence will not completely derail the talks taking place in Cairo but according to early reports, Israeli negotiators have already left Egypt.
Hamas rejected Egyptian attempts to extend the truce, demanding that Gaza’s harbour be re-opened for shipping. Israel suspects Hamas could use the harbour as a means to smuggle more sophisticated weapons from Iran and elsewhere in the Middle East.
According to Palestinian health officials, so far at least 1,875 people have died in the four-week conflict, while the Israeli government says 64 soldiers have been killed along with two civilian Israelis and a Thai farm worker.
Israel also claims that it has killed around 900 militants from Hamas and other militant factions in the fighting.