JERUSALEM ø Prime Minister Ariel Sharon asserted that Irael had reached an understanding with the United States concerning Iran's nuclear weapons arsenal.

Sharon told the Knesset Foreign Affairs and Defense Committee on Wednesday that he and President George Bush agreed to a series of strategic understandings concerning Israel's defensive posture in the Middle East. Sharon said the understandings were among the benefits offered by the Bush administration for the prime minister's pledge to unilaterally withdraw from the Gaza Strip and the northern West Bank.

The prime minister said one of the U.S. benefits concerned "defense against a weapons of mass destruction attack against Israel," a participant at the meeting said. Sharon did not elaborate. But the participant said the reference was to Iran's emerging nuclear weapons program.

Over the last two weeks, Sharon's Cabinet has been mulling revisions to the plan, Middle East Newsline reported. A key aide of the prime minister met U.S. National Security Adviser Condoleezza Rice on June 1 to report on Sharon's efforts to win Cabinet approval of the withdrawal program.

Earlier, Israeli sources said Bush and Sharon discussed Iran's nuclear weapons program without their aides during their White House summit on April 14.

[On June 1, the U.S. Defense Security Cooperation Agency informed Congress that the United States intends to sell the Joint Direct Attack Munitions, or JDAMs, to Israel. The Pentagon agency said the sale could total $319 million.]

U.S. analysts and government sources said the Bush administration has discussed the prospect of an Israeli air strike at several levels of government. They said the issue has been examined in terms of the diplomatic, military and security implications for the United States, particularly its military presence in Iraq and the Persian Gulf region.

"Our focus is on getting Iran to end its nuclear program, and we are continuing to work with the international community to urge Iran to take to end its nuclear programs," White House press secretary Scott McClellan said on Wednesday.

The administration has not linked the Sharon plan with any U.S. pledge regarding Iranian or Middle East WMD programs. But U.S. officials said any White House guarantees provided to Sharon were restricted to the plan presented to the administration in April.

"We support that plan and no other plan," State Department spokesman Richard Boucher said on Wednesday. "So we have not been presented with any other plan at this point. We went through this very carefully with the Israelis and found that we could support this plan."

The Bush administration has been concerned by the muted but repeated Israeli warnings that the Jewish state would not tolerate the development of an Iranian nuclear arsenal. Over the last year, Sharon has been urged by leading Israeli strategists to consider a preemptive strike on Iranian nuclear facilities. Israeli military intelligence has assessed that Iran could achieve indigenous nuclear weapons capability in 2005.

"Israel will do whatever possible to prevent an enemy coalition from being formed and from coming into possession of WMD [weapons of mass destruction]," a panel of Israeli and U.S. strategists said in a report to Sharon in April. "This could include pertinent preemptive strikes ø conventional ø against enemy WMD development, manufacturing, storage, control and deployment centers. This recommendation is consistent both with longstanding international law regarding 'anticipatory self-defense' and with the newly-stated defense policy of the United States of America."

In his session with the Knesset committee, Sharon outlined his four-stage withdrawal plan from the Gaza Strip and northern West Bank. In the first stage, Israel would dismantle the communities of Kfar Darom, Morag and Netsarim; in the second stage, Israel would evacuate the northern West Bank communities of Ganim, Homesh, Kadim and Sa-Nur.

In the third stage, Israel would withdraw from the Gush Katif bloc of communities. In the last stage, the communities of the northern Gaza Strip, including Alei Sinai, Dugit and Nissanitm, would be dismantled.

For his part, Bush asserted in a speech to U.S. Air Force cadets that Sharon's plan would facilitate the establishment of a Palestinian state.

Bush said the Sharon plan requires the support of what he termed reform-minded Palestinians to "step forward and lead and meet their road map obligations."

"Prime Minister Sharon's plan to remove all settlements from Gaza and several from the West Bank is a courageous step toward peace," Bush said.

"His decision provides an historic moment of opportunity to begin building a future Palestinian state. This initiative can stimulate progress toward peace by setting the parties back on the road map, the most reliable guide to ending the occupation that began in 1967."