As U.S. National Security Adviser Tom Donilon arrived in Saturday night to discuss the Iranian nuclear issue with top Israeli officials, a U.S. official has told Haaretz that all the messages from Israel in recent months pointed to the likelihood of an Israeli strike on Iran.

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Donilon is set to meet with Prime Minister Benjamin Netanyahu and advisers on Sunday, as part of preparations for Netanyahu's scheduled visit to Washington, D.C. next month, which will include a meeting with President Barack Obama.

That visit is also expected to focus on Tehran's nuclear program, as well as U.S. concerns that Israel is planning to attack Iranian atomic facilities within a few months.

Speaking to Haaretz on condition of anonymity, a senior U.S. official said that in the past six months the messages reaching Washington from Jerusalem have increasingly pointed to the likelihood of an Israeli strike, more so than in the previous two years. "We think that Israel still has not decided whether to attack or not, but it is clear to us that it is being considered seriously," he said.

The U.S. administration wants Israel to wait a few months in order to give the international sanctions against Iran a chance before deciding on an attack. A few days ago, officials in Tehran expressed a readiness to resume negotiations with the six main powers.

Israeli officials have expressed some satisfaction with the latest anti-Iran sanctions. On Friday the Belgium-based SWIFT, which provides banks with a system for moving funds around the world, bowed to international pressure and said it was ready to block Iranian banks from using its network to transfer money. But Jerusalem does not believe that even these measures will lead Tehran to reevaluate its nuclear plans.

On Sunday, Netanyahu is expected to tell Donilon that the only test of the sanctions is a positive outcome. "Any measure that doesn't stop Iran's nuclear program is inadequate," a senior Israeli government aide said recently.

Speaking to reporters in Tokyo on Saturday, Defense Minister Ehud Barak said Israeli military action against Iran is not on the table for now, and called for "crippling and consequential" sanctions against Iran.

The Israeli government source said U.S. and Israeli teams will work together during Donilon's visit. The Israeli team is headed by national security adviser Yaakov Amidror, with representatives from the defense, foreign and strategic affairs ministries, as well as from army intelligence.

Donilon will leave Israel tomorrow. His entourage includes senior White House, State Department and Department of Defense officials such as Gary Samore, White House coordinator for arms control and weapons of mass destruction, and White House Middle East Adviser Steve Simon.

Donilon is scheduled to meet with Barak and will presumably also speak with IDF Chief of Staff Lt. Gen. Benny Gantz and Mossad chief Tamir Pardo. The White House said in a statement that talks will also include the situation in Syria.

In other news affecting the region, U.S. Secretary of Defense Leon Panetta warned on Friday of the dangers facing the United States in the Middle East. Speaking at a "town hall meeting" with officers and soldiers at a U.S. Air Force base in Barksdale, Louisiana, Panetta recited a long list of challenges facing the United States military establishment in an era of deep government cutbacks.

"We face the whole issue of rising turmoil in the Middle East," Panetta said. "I mean, God, any one of those countries in the Middle East could blow on us - from Syria, which is already in turmoil, to Egypt, to Yemen, to a number of others."

Panetta's warning came just days after the chairman of the Joint Chiefs of Staff, U.S. Army Gen. Martin E. Dempsey, failed, in a visit to Egypt, to dissuade Cairo from going ahead with criminal proceedings against 19 Americans affiliated with prodemocracy organizations in the country.

Officially, U.S. military authorities said that Dempsey's trip "was planned long before this situation developed and caused tension between the two nations."

Speaking to a reporter with the American Forces Press Service on his flight from Cairo to Washington, Dempsey said: "We discussed that [situation] very professionally," adding, "I expressed the fact that it caused us concern, not only about the particular NGOs and individuals currently unable to leave the country, but rather more broadly."

Dempsey's relationship with his Egyptian counterpart, Lt. Gen. Sami Hafez Enan, as well as Field Marshal Mohamed Hussein Tantawi, began in 2007 when Dempsey was deputy commander of U.S. Central Command and continued after he became acting commander in 2008.

Dempsey said he asked the defense leaders, "What signal should I take from this in terms of how you see Egypt's future? Are you going to become isolated? Are you going to preserve individual freedoms or deny them?" He noted that "they don't have the answers right now."

Dempsey said he found the Egyptian military "quite eager" to get out of the country-running business.

Meanwhile, on Friday it was reported that two Iranian naval ships sailed through Egypt's Suez Canal into the Mediterranean.

"Two Iranian ships crossed through the Suez Canal following permission from the Egyptian armed forces," a source in the canal authority said, adding that the destroyer and a supply ship could be on their way to the Syrian coast. Iran and Syria agreed to cooperate on naval training a year ago, and Tehran has no naval agreement with any other country in the region.

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