Israel Pounds Hamas in Gaza

Israel has continued bombing Gaza for a fourth day, hitting government buildings in Gaza City today and threatening a drawn-out conflict as the toll of Palestinians killed rose to at least 364.

Palestinian militants stepped up rocket attacks that on Monday killed three Israeli civilians in towns in southern Israel: among them, a woman was killed at a bus stop in the city of Ashdod, the furthest north a rocket from Gaza has so far reached, and a soldier was killed by a mortar fired from Gaza.

Early today, Israeli planes dropped at least 16 bombs on five government buildings in Gaza, destroying them and starting several fires.

Ehud Barak, Israel's defence minister, who has said his government does not want another ceasefire with Hamas, said his army was fighting a "war to the bitter end". Israel declared the border area around Gaza a closed military zone – together with preparations to call up thousands of reservists, this could suggest a large ground invasion is planned next. Barak said the military campaign would be "widened and deepened as needed".

The number of civilians killed has continued to rise. The UN Relief and Works Agency, which supports Palestinian refugees and has large programs in Gaza, said it believed at least 62 civilians were dead at a conservative estimate. The overall number of injured is thought to be as high as 1,400, although Gazan hospitals are so overcrowded and short of medicine and equipment that they are turning away all but the most seriously wounded.

The Israeli interior minister, Meir Sheetrit, said there was "no room for a ceasefire" with Hamas until the threat of rocket fire had been removed. "The Israeli army must not stop the operation before breaking the will of the Palestinians, of Hamas, to continue to fire at Israel," he told Israel Radio. Matan Vilnai, Israel's deputy defence minister, said the military "has made preparations for long weeks of action".

Ban Ki-moon, the UN secretary general, called for swift and decisive action to end the "unacceptable" violence and urged world leaders to step up pressure for a political solution. In his third statement on Gaza in three days, Ban said he was "deeply alarmed" by the escalation of violence. While recognizing Israel's right to defend itself, he condemned its "excessive use of force".

The Bush administration refused to call on Israel to show restraint, instead blaming the conflict solely on Hamas rocket attacks from Gaza into Israel. "Israel is going after terrorists who are firing rockets and mortars into Israel, and they are taking the steps that they feel are necessary to deal with the terrorist threat," said Gordon Johndroe, a White House spokesman.

"In order for the violence to stop, Hamas must stop firing rockets into Israel and agree to respect a sustainable and durable ceasefire."

Israel had told the US it was not planning to retake Gaza, Johndroe said.

Apart from anger in the Arab world, governments elsewhere have been quiet, with little public criticism of Israel – in contrast with previous similar offensives.

The Pope had been scheduled to make his first trip to Israel in May, but a spokesman, interviewed by Vatican radio, said this was no longer certain. "There is a need to be rather prudent," Father Federico Lombardi said. The pontiff urged both sides to restore a truce and not to yield to the "perverse logic of confrontation and violence".

In Damascus, a senior Hamas leader said the group's conditions for a fresh ceasefire were a halt to Israeli attacks in Gaza and the West Bank and a reopening of the crossings into Gaza – conditions Israel has previously refused.

"We are going to defend ourselves, defend our people and defend our land," Moussa Abu Marzouk, the deputy head of the Hamas politburo, told AP. "We need our liberty, we need our freedom and we need to be independent. If we don't accomplish this objective then we have to resist. This is our right." Hamas leaders in Gaza were in hiding last night.

One of Israel's targets in bombing raids before dawn yesterday was the Islamic University in Gaza City, the territory's main university and one with links to Hamas. Two buildings housing science and engineering laboratories were flattened and six others damaged.

Gaza's streets were empty again and Israeli military drones and jets could be heard overhead. The only crowds were queues at bakeries. Israel again prevented journalists from entering Gaza to report on the bombing.