U.S. Defense Secretary Leon Panetta reportedly failed in his bid to have Israel clear any attack on Iranian nuclear facilities with the United States.

Panetta in a visit to Israel last month tried to get a commitment from Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak that Israel would clear any operation on Iranian nuclear facilities, Haaretz reported Sunday.

Iranian nuclear efforts now are solely related to bomb making, according to sources briefed on a report set to be released Wednesday by the International Atomic Energy Agency, the nuclear watchdog of the United Nations. The sources, including diplomats, told news services that the report will show that Iran has developed computer models of a working nuclear warhead and constructed a steel box the size of a bus in which to conduct nuclear weapons tests.

Previous IAEA reports have said that Iran has enough low-grade enriched uranium that if enriched to a higher percentage, which it has the capacity to do, could create four to five nuclear bombs, according to the Israeli daily Haaretz.

Israeli President Shimon Peres told Israel Channel 2 over the weekend that an Israeli attack on Iran is "more and more likely." Peres' comments come following a week in which Israel's media reported widely that Netanyahu and Barak were attempting to convince the Cabinet to authorize a military strike on Iranian nuclear production sites.

Peres said Sunday that the international community must take action to halt Iran's nuclear drive.

"Leaders from many countries pledged not to allow Iran to obtain nuclear weapons, and we need to demand that they meet those commitments," he said during an interview with Army Radio.

Iran is reported to be about six months away from becoming a nuclear power.