JERUSALEM — Israel will set up a security zone in southern Lebanon until an international force arrives to secure the border, the Israeli defense minister, Amir Peretz, said yesterday.

The announcement further reduced hopes of an early end to the fighting, which raged unabated as Israel pressed on with a ground attack and launched more than 100 airstrikes.

Hezbollah responded with rocket attacks, hitting the city of Haifa. The fighting raised the death toll in Lebanon to at least 411, while 42 Israelis have been killed.

The violence coincided with a visit by Secretary of State Rice to Israeli and Palestinian Arab leaders. Ms. Rice voiced concern at the suffering of “innocent people throughout the region” but did not demand an immediate halt to the fighting.

She repeated Washington’s wish for an “enduring cease-fire,” an indication of its backing for Israel’s war aim of destroying Hezbollah militarily and adjusting the regional balance of power.

She also announced that America sought to forge a “new Middle East” from the crisis in Lebanon, in a signal that Washington’s grand ambitions for the region have not died in Iraq.

Standing next to Prime Minister Olmert, Ms. Rice made it clear that the White House viewed the conflict between Israel and Hezbollah militants as an ideological battle.

“It is time for a new Middle East,” she said. “It is time to say to those that don’t want a different kind of Middle East that we will prevail. They will not.”

The immediate American emphasis is on providing humanitarian help to the estimated 750,000 Lebanese who have been driven from their homes by the fighting. Discussions are under way to set up an international protection force to secure an aid corridor to the affected areas, to which Israel has in theory agreed.

They will intensify at an international meeting in Rome today where Ms. Rice will preside.The meeting also will consider plans for a multinational peace force to stabilize the border area. Momentum for the deployment, first mooted by Prime Minister Blair and Secretary-General Annan, has gathered after Israel unexpectedly gave its backing.

Israeli officials envisage a force of up to 20,000, preferably NATO-led, which would hold a strip stretching up to six miles into Lebanon and control border crossings with Syria to block Hezbollah resupplies. A force could be in place one to two weeks after approval, they said. But diplomats warned that the idea was in its infancy and an agreement in principle was all that was likely to emerge from the conference. NATO is heavily engaged overseas, and Britain and America have already said they will not contribute.

Governments will be reluctant to place their troops in Hezbollah’s line of fire. The group is likely to regard any deployment as an affront and resist attempts to disarm it, as demanded by a recent U.N. Security Council resolution.

The Italian prime minister, Romano Prodi, who is hosting the talks, said the main aim was to obtain an immediate cease-fire.

Israel, which will not be present, is insisting that Hezbollah withdraw from the south of Lebanon and return two captured Israeli soldiers without conditions, as the price of halting its offensive. America is giving its backing.

The chances of a lull faded further after Mr. Peretz announced the establishment of a buffer zone in southern Lebanon. The Israeli presence seems certain to maintain the tempo of violence and reduce the prospect of early international deployment. European potential contributors have insisted on a cease-fire before any troops can be sent.

Yesterday, the Israeli ground offensive continued, with the army claiming it had taken control of Bint Jbeil, a Hezbollah stronghold just inside Lebanon. It said 20 to 30 “terrorists” were killed. Aircraft also struck buildings in south Beirut in what was seen as an attempt to kill the Hezbollah leader, Sheik Hassan Nasrallah. The conflict continued to claim innocent victims: An Israeli airstrike on a village killed a family of seven, and in Haifa, a 15-year-old girl died in a Hezbollah missile attack.