UPDATE 3: Hamas retaliates with rocket fire, Israel mulls ground offensive.
Israeli jets bombed Hamas targets in Gaza for a third day on Monday, killing several children, while the Islamists fired deadly rockets to retaliate for the blitz that has left more than 300 dead.
As Israeli tanks massed on the Gaza border, the army declared the area a closed military zone - a move that in the past has often been followed by ground operations in the Palestinian enclave.
Amid mounting international calls for an end to the violence, Israel allowed the passage of humanitarian aid into the impoverished and overcrowded territory where most of the 1.5 million population depends on foreign aid.
Hamas militants remained defiant on Monday, firing some 20 rockets into Israel.
An Israeli Arab was killed and eight other people were wounded when one of the projectiles slammed into a construction site in the southern city of Ashkelon some 13 kilometres (eight miles) north of the Gaza border.
The Israeli blitz, unleashed on Saturday in retaliation for ongoing rocket and mortar fire from Gaza, has killed at least 312 Palestinians and wounded more than 1,400 others, according to Gaza medics.
At least 51 civilians were mong the dead, the UN Palestinian refugee agency said. "We have 51 confirmed civilian casualties including women and children," said UNRWA spokesman Christopher Gunness.
Among those killed in fresh raids overnight were four girls from the same family aged from one to 12 years old.
They died in an air raid in the northern town of Jabaliya that targeted a mosque near their home, while two boys were killed in a strike on the southern city of Rafah, medics said.
China and Japan joined the growing international chorus for a halt to the violence, which has also included Britain, France and Russia.
Hamas, the Islamist Palestinian movement branded a terror group by Israel and the West, lashed out at the world for not doing enough to end the blitz.
Israel is "committing a holocaust as the whole world watches and doesn't lift a finger to stop it," Hamas spokesman Fawzi Barhum told reporters.
The Islamist group "reserves the right to hit back at this aggression with martyr operations," meaning suicide bombings of the sort Hamas has not carried out inside Israel since January 2005, he said.
Egyptian Foreign Minister Ahmed Abul Gheit arrived in Ankara on Monday for talks with Turkish leaders on the Israeli offensive. Egypt had said on Sunday that it was trying to broker a ceasefire , although an Israeli official said the Jewish state was not interested in a truce.
Since the start of the Israeli onslaught on Saturday, Gaza militants have fired more than 100 rockets and mortars into the Jewish state, killing two people and wounding nearly two dozen more.
Some of the rockets landed some 30 kilometres (18 miles) inside Israel, the farthest yet.
Israel opened the Kerem Shalom crossing in Gaza's south on Monday, with 80 trucks filled with medicine and food expected to pass through, a military spokesman told AFP.
Amid vows by Israeli Defence Minister Ehud Barak to expand the air blitz and to send in ground troops if necessary, the Israeli cabinet on Sunday gave the green light to call up 6,500 reserve soldiers.
The Israeli offensive has sparked protests across the world, with demonstrations held in European capitals, Turkey, Egypt and Syria. At least two Palestinians were killed with clashes with Israeli security forces during protests in the occupied West Bank.
At a rally in Tehran, thousands of Iranians shouted "Down with Israel" and "Down with the USA" as they carried banners reading "We should all rise and destroy Israel."
Israel unleashed "Operation Cast Lead" against Hamas in the middle of Saturday morning, with some 60 warplanes bombing more than 50 targets in just a few minutes.
The Israeli blitz came after days of spiralling violence since the expiry of the Gaza truce. It comes less than two months before snap parliamentary elections in Israel called for February 10.
We are drawn to the criminal activities in other parts of the World especially Africa however it would appear that the international press appear to turn a blind eye to the atrocities inflicted upon Palestine over many years by Israel however, they do focus on any retaliation metered out by Palestinian freedom fighters. these groups would probably not exist if it were not for the annexation and apartheid policies allowed by Israel's past and current governments. This is fronted by every Israeli government leader from Ben Gurion to the present. When they are critisesed they play their sympathy card "remember the Holocaust" Yes we do but what they are doing is more cruel and has been sustained for a lot longer. I wonder how long the collective and LEGAL nations of the regions' patience can last - and when will American and British Politics stop their long appesement for Jewish money and votes.
The inaction of neighbouring countries makes me wonder if there is any brotherhood left at all...that we are all letting children, men, women die without any action ..except pointless rhetoric by so called "world leaders". It is shameful! My heartfelt condolences for all innocent civilians who have lost their near and dear one's in this barbaric slaughter.
Who are the real terrorist? As innocent people including women and children , 80% of them who live solely on aids , get massacred in their homes , what reason and justification do you want to hear on it ?How many more people have to die before we act and raise our voice against what is pure cruelty! State of Israel continues to defy the UN and yet is USA's strongest ally, is this fair or double standards? why aren't the world's most popular publications condemning the murders being committed in the front of the world eye's ? why is this not terrorism ? why ?