Navy joins bombardment of Hamas terrorist bases

Planes struck a house next to the Hamas prime minister's home, devastated a security compound and flattened a five-storey building at a university closely linked to the Palestinian Islamic militant group. The Israeli navy joined the attack, launching a bombardment from the sea.

Hamas responded by firing rockets deeper into Israel than ever before. Missiles hit targets up to 23 miles from the Gaza strip, leaving two dead and 15 injured.

An Israeli was killed today in the southern city of Ashkelon, 10 miles north of Gaza, in a rocket attack that wounded seven others.

Today Israel declared a buffer zone around Gaza up to four kilometres wide as a "closed military zone". A military spokesman said the new policy meant that civilians, including journalists, may be barred from the area, opening the way for a ground assault. Tanks have massed on the border and 6,500 reserve soldiers have been put on standby. Israel today warned it will fight a "war to the bitter end" as it intensified its air raid in the deadliest blitz of the Palestinian territory. The country's defence minister said the offensive would be as "widened and deepened as needed."

Ehud Barak said the operation would continue and even intensify with the goal to force militants to stop "hostile actions" against Israeli civilians. He said: "We have a war to the bitter end against Hamas and its branches." A spokesman for Israeli prime minister Ehud Olmert said the military action would go on until the population in southern Israel "no longer live in terror and in fear of constant rocket barrages".

The three-day campaign has left at least 310 Palestinians dead and another 1,400 wounded. There are reports that Hamas military commander Ahmed Ja'abriwho may have been killed.

"We took Hamas by surprise, we targeted Hamas headquarters, so this is the beginning of a successful operation, I hope, but the idea is to change realities on the ground," said Israeli Foreign Minister Tzipi Livni.

In recent months Gaza's Hamas rulers have been attacking targets deeper and deeper inside Israel. Yesterday, Palestinian missiles were fired into the city of Ashdod, 23 miles from Gaza.

Officials said that Hamas was believed to still have thousands of Kassam rockets as well as many Katyushas. It is feared Hamas may also have rockets with ranges greater than 25 miles as well as advanced anti-tank and anti-aircraft missiles.

Israeli missiles have wrought unprecedented destruction in Gaza, reducing whole buildings to rubble. It army has hit targets in all Gaza's main towns, including Gaza City in the north and Khan Younis and Rafah in the south. Other targets were a guest palace used by the Hamas government and the house next to Gaza Hamas leader Ismail Haniyeh's home in a refugee camp next to Gaza City. He was not home, as Hamas leaders have gone into hiding.

The air raids have also struck security compounds, government offices and tunnels into Egypt which have provided a lifeline for the territory during the Israeli blockade.

Ewa Jasiewicz, of the Free Gaza Movement in Bayt Lahiya, said she had seen TV reports of a helicopter bombing a mosque and killing five girls. "Because Gaza is so densely populated, there is no such thing as precision strike - you have glass, brick, shrapnel flying into people's homes," she said.

Hundreds of Palestinians stormed a fence on the Gaza-Egypt border, but Egyptian forces fired shots to prevent them entering. An Egyptian security official was shot dead and another wounded in the turmoil.