Heavy fighting is reported in Gaza between Israeli forces and Palestinian fighters after Israel launched its ground offensive on the territory.
Thousands of Israeli troops entered the Gaza Strip overnight with tanks and helicopters, accompanied by naval support and air strikes.
At least 30 Palestinians, mostly civilians, have been killed since ground fighting began late on Saturday, according to Palestinian medical sources.
More than 500 Palestinians have been killed in the nine days of what's been termed "Operation Cast Lead" and four Israelis have been killed by the Hamas rocket strikes in the same time.
While the UN secretary general called for an immediate end to the operations, the Security Council failed to agree on a resolution calling for a ceasefire after an emergency meeting.
Al Jazeera's Sherine Tadros, reporting from the Shifa hospital in Gaza, said doctors were struggling to cope amid low supplies and the rising number of wounded.
She said the scene was chaotic, with doctors treating the injured on the floor.
Soldiers and fighters were also locked in gunbattles east of the Hamas stronghold of Zeitoun.
Al Jazeera's Ayman Mohyeldin, reporting from Gaza City said: "Perhaps the most significant military development on the ground is that Gaza has now actually been split into two.
"A column of Israeli tanks and artillery, and armoured personnel vehicles has made its way through from the eastern part of Gaza, reaching as far as the Mediterrannean sea on the Western part, essentially splitting Gaza.
However, the military has confirmed that at least 30 soldiers have been wounded in the fight so far, two of them seriously.
Al Aqsa TV, the station affiliated to Hamas, said the group has captured two Israeli soldiers. This has not been independently verified nor has the Israeli military confirmed it.
"As far as we know, this is not true," a senior army official told reporters.
In initial clashes, Israeli ground forces killed eight Gazans, five of them fighters.
Ayman Mohyeldin, Al Jazeera's correspondent in Gaza City, said that the scene in Gaza was one of "fear and terror".
Palestinian medical sources say at least 477 Palestinians have died and more than 2,300 had been injured since Israel began aerial bombardment of Gaza more than a week ago.
Four Israelis have also been killed by Palestinian rockets fired into southern Israel during the past week.
Israel, meanwhile, extended its naval blockade of Gaza early on Sunday, from six nautical miles to 20 nautical miles, preventing humanitarian aid and protest vessels from trying to break the siege.
Around 9,000 military reservists have also been called up to assist in the ground assault.
Ehud Barak, Israel's defence minister, said on Saturday that the operation was aimed at forcing Hamas "to stop its hostile activities against Israel and bring about significant change".
"We have carefully weighed all our options, we are not war hungry but we should not allow a situation where our towns are constantly targeted by Hamas," he said.
"Ultimately Hamas is solely responsible for this crisis and today they are paying a price for that," he said.
Hamas has vowed to defeat the Israeli army following the invasion, with Osama Hamdan, a senior official for Hamas in Beirut, Lebanon, telling Al Jazeera that "military operations will not win for the Israelis".
On Friday, Khaled Meshaal, the political leader of Hamas, had warned that any Israeli ground offensive would lead to a "black destiny".
Al Jazeera's Ayman Mohyeldin reports that power lines have been cut throughout the Gaza Strip and more than 250,000 people in the northern part of the territory are without electricity.
"The biggest concern is a ground invasion could result in urban warfare," he said.
"Rockets are being fired from deeper and deeper within Gaza and if Israel's intention is to prevent such attacks how far into Gaza, an area densely populated with civilians, will they need to go?"
Fears of a humanitarian crisis have also grown in recent days, as the strip, home to 1.5 million people, is already suffering shortages of fuel, food and medical supplies due to a two-year economic blockade imposed by Israel.
The International Committee for the Red Cross said on Saturday its medical emergency team had been prevented for a second day from entering the territory.
The UN has warned that there were "critical gaps" in aid reaching Gaza, despite claims from Tzipi Livni, the Israeli foreign minister, that there was no crisis and that aid was getting through.
At least 25 per cent of the Palestinians killed since Israel began its aerial assault nine days ago were civilians, the UN has estimated.
04 January 2009
[NEWS]Israel pushes deeper into Gaza
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