Breaking NewsChildren Killed In Gaza Airstrike
Israeli tanks massing on the Gaza border Israel May Call Truce 1:48
Blast as missiles fired from an Israeli aircraft strike in northern Gaza Strip
Brothers Iyad, Mohammed and Abdelsattar al-Astal, aged seven to 10, were killed while they played on a street in southern Gaza, according to witnesses.
The missile strike may have been targeting a rocket launching pad near their home in al-Qarara.
With tanks and troops massed for a threatened ground offensive and with no ceasefire in sight, Israeli planes and naval guns staged more than 50 bomb attacks.
An Israeli army spokeswoman said the overnight bombing targeted rocket launchers and weapons storage facilities.
Witnesses in Gaza said several people had been wounded in the attacks, but no deaths were reported.
Hamas has continued to fire rockets deep into Israel.
Israel has allowed 200 foreigners to leave Gaza as the death toll from the seven-day blitz reached at least 420, including the killing of a top Hamas commander.
Residents with dual citizenship have been passing through the Erez crossing at the request of their own governments, an Israeli defence ministry spokesman told Sky News.
"They're people married to Palestinians, when they were abroad and they came here and they've been here for years and at this time they've asked to leave due to the tension," spokesman Peter Lerner said.
He denied reports Israel had ordered the foreigners to go.
Many of those leaving are from the United States, Russia and Ukraine.
Palestinian-American Joanne Haji spoke to Sky's Dominic Waghorn at the crossing.
You know how it feels waiting for death? Yes it's very strong, it's very bad.
Palestinian-American Joanna Haji describes Gaza
"We don't know how to sleep, there's no food, there's nothing. And Arabs are not moving and they're supposed to move. If you go see Gaza it's like an unliving country," she said.
Israeli and Egyptian borders remain closed, with no one else able to pass through.
On Thursday, Israeli jets fired missiles on the home of hardline Hamas figure Nizar Rayan in the Jabaliya refugee camp.
The attack killed him, his four wives, 10 of his children and two neighbours, witnesses and medical sources said.
Rayan's headless body was hurled into the street by the force of the blast, which also destroyed or damaged 12 nearby houses.
Considered to be among the most hawkish of Hamas leaders, Rayan was the most senior figure to be killed by Israel since Abdel Aziz al Rantissi in 2004.
Hamas leader Ismail Radwan said: "This cowardly enemy must realise that he will regret these crimes against our people."
He called for a 'day of wrath' to avenge his death.
In addition to the 420 dead, Israel's Operation Cast Lead has also left more than 2,100 people wounded, according to Palestinian emergency services.
Hamas Rocket Strikes On IsraelDec 31st Over 100 (approximate figure)
30th 70 rockets
29th 80 rockets (approximate figure)
28th 40 rockets, mortar rounds and two Grad missiles
27th 110 rockets, mortar rounds, including a Grad-Katyusha
Boxing Day 25 mortar rounds
Christmas Day 7 Qassam rockets, one Grad, nine mortar rounds
Christmas Eve & 23rd 33 rockets (Grad-Katyushas and Qassams), 37 mortar shells
22nd 2 Qassams, 1 mortar
21st 19 Qassams, 3 mortars
20th 10 Qassams
Source: Israeli Defence Force
Rocket fire from Gaza has killed four people and wounded dozens in Israel.
Thursday's Israeli strikes also reportedly hit the parliament and justice ministry, rocket launching sites, tunnels for smuggling weapons or supplies into the territory and weapons storage facilities.
The New Year Resolution of Hamas and Israel is each to stand firm until the other cracks.
Sky News foreign affairs editor Tim Marshall's blog
Hundreds of houses have been destroyed and the United Nations says about 25% of the dead are civilians.
Food, fuel and medical supplies are all running short, aid agencies say.
Israel began the offensive on Saturday in response to rocket fire by Hamas and its allies but has failed to halt those attacks.
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