aid. Its disclosure threatens to anger Arab governments and others because of the appearance that the United States is actively aiding the Israeli bombing campaign in a way that could be compared to Iran's efforts to arm and resupply Hezbollah.

The munitions that the United States is sending to Israel are part of a multimillion-dollar arms sale package approved last year that Israel is able to draw on as needed, the officials said. But Israel's request for expedited delivery of the satellite and laser-guided bombs was described as unusual by some military officers, and as an indication that Israel still had a long list of targets in Lebanon to strike.

Secretary of State Condoleezza Rice said Friday that she would head to Israel on Sunday at the beginning of a round of Middle Eastern diplomacy. The original plan was to include a stop to Cairo in her travels, but she did not announce any stops in Arab capitals.

Instead, the meeting of Arab and European envoys planned for Cairo will take place in Italy, Western diplomats said. While Arab governments initially criticized Hezbollah for starting the fight with Israel in Lebanon, discontent is rising in Arab countries over the number of civilian casualties in Lebanon, and the governments have become wary of playing host to Ms. Rice until a cease-fire package is put together.

To hold the meetings in an Arab capital before a diplomatic solution is reached, said Martin S. Indyk, a former American ambassador to Israel, "would have identified the Arabs as the primary partner of the United States in this project at a time where Hezbollah is accusing the Arab leaders of providing cover for the continuation of Israel's military operation."

The decision to stay away from Arab countries for now is a markedly different strategy from the shuttle diplomacy that previous administrations used to mediate in the Middle East. "I have no interest in diplomacy for the sake of returning Lebanon and Israel to the status quo ante," Ms. Rice said Friday. "I could have gotten on a plane and rushed over and started shuttling around, and it wouldn't have been clear what I was shuttling to do."

Before Ms. Rice heads to Israel on Sunday, she will join President Bush at the White House for discussions on the Middle East crisis with two Saudi envoys, Saud al-Faisal, the foreign minister, and Prince Bandar bin Sultan, the secretary general of the National Security Council.

The new American arms shipment to Israel has not been announced publicly, and the officials who described the administration's decision to rush the munitions to Israel would discuss it only after being promised anonymity. The officials included employees of two government agencies, and one described the shipment as just one example of a broad array of armaments that the United States has long provided Israel.

One American official said the shipment should not be compared to the kind of an "emergency resupply" of dwindling Israeli stockpiles that was provided during the 1973 Arab-Israeli war, when an American military airlift helped Israel recover from early Arab victories.

David Siegel, a spokesman for the Israeli Embassy in Washington, said: "We have been using precision-guided munitions in order to neutralize the military capabilities of Hezbollah and to minimize harm to civilians. As a rule, however, we do not comment on Israel's defense acquisitions."

Israel's need for precision munitions is driven in part by its strategy in Lebanon, which includes destroying hardened underground bunkers where Hezbollah leaders are said to have taken refuge, as well as missile sites and other targets that would be hard to hit without laser and satellite-guided bombs.

Pentagon and military officials declined to describe in detail the size and contents of the shipment to Israel, and they would not say whether the munitions were being shipped by cargo aircraft or some other means. But an arms-sale package approved last year provides authority for Israel to purchase from the United States as many as 100 GBU-28's, which are 5,000-pound laser-guided bombs intended to destroy concrete bunkers. The package also provides for selling satellite-guided munitions.

An announcement in 2005 that Israel was eligible to buy the "bunker buster" weapons described the GBU-28 as "a special weapon that was developed for penetrating hardened command centers located deep underground." The document added, "The Israeli Air Force will use these GBU-28's on their F-15 aircraft."

American officials said that once a weapons purchase is approved, it is up to the buyer nation to set up a timetable. But one American official said normal procedures usually do not include rushing deliveries within days of a request. That was done because Israel is a close ally in the midst of hostilities, the official said.

Although Israel had some precision guided bombs in its stockpile when the campaign in Lebanon began, the Israelis may not have taken delivery of all the weapons they were entitled to under the 2005 sale.

Israel said its air force had dropped 23 tons of explosives Wednesday night alone in Beirut, in an effort to penetrate what was believed to be a bunker used by senior Hezbollah officials.

A senior Israeli official said Friday that the attacks to date had degraded Hezbollah's military strength by roughly half, but that the campaign could go on for two more weeks or longer. "We will stay heavily with the air campaign," he said. "There's no time limit. We will end when we achieve our goals."

The Bush administration announced Thursday a military equipment sale to Saudi Arabia, worth more than $6 billion, a move that may in part have been aimed at deflecting inevitable Arab government anger at the decision to supply Israel with munitions in the event that effort became public.

On Friday, Bush administration officials laid out their plans for the diplomatic strategy that Ms. Rice will pursue. In Rome, the United States will try to hammer out a diplomatic package that will offer Lebanon incentives under the condition that a United Nations resolution, which calls for the disarming of Hezbollah, is implemented.

Diplomats will also try to figure out the details around an eventual international peacekeeping force, and which countries will contribute to it. Germany and Russia have both indicated that they would be willing to contribute forces; Ms. Rice said the United States was unlikely to.

Implicit in the eventual diplomatic package is a cease-fire. But a senior American official said it remained unclear whether, under such a plan, Hezbollah would be asked to retreat from southern Lebanon and commit to a cease-fire, or whether American diplomats might depend on Israel's continued bombardment to make Hezbollah's acquiescence irrelevant.

Daniel Ayalon, Israel's ambassador to Washington, said that Israel would not rule out an international force to police the borders of Lebanon and Syria and to patrol southern Lebanon, where Hezbollah has had a stronghold. But he said that Israel was first determined to take out Hezbollah's command and control centers and weapons stockpiles.

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Thom Shanker contributed reporting for this article.