U.S. Secretary of Defense Leon Panetta visited Israel Monday with a clear message from his boss in Washington: The United States opposes any Israeli attack on Iran's nuclear facilities.

At a joint press conference with Defense Minister Ehud Barak, Panetta stressed that any steps against Iran's nuclear program must be taken in coordination with the international community.

The United States, he said, is "very concerned, and we will work together to do whatever is necessary" to keep Iran from posing "a threat to this region." But doing so "depends on the countries working together," he added.

He repeated the word "together" several times in this context.

Panetta cited Iran's nuclear program as number one on the list of issues he had discussed with Barak. He voiced concern not only about the nuclear program, but also about Iran's support for terror, its efforts to undermine regional stability and the fact that it had supplied weapons that were used to kill American soldiers.

At the press conference, which took place at Defense Ministry headquarters in Tel Aviv, Panetta also stressed America's deep commitment to Israel's security.

His message for Barak, at their second meeting in two weeks, appeared to be simultaneously embrace and restrain: America is standing by Israel, but an uncoordinated Israeli strike on Iran could spark a regional war. The United States will work to defend Israel, but Israel must behave responsibly.

Washington has been worried by statements various senior Israeli officials have made recently that seemed to take an aggressive line on Iran. The issue has taken on new urgency because, in the view of many Western military experts, the window of opportunity for an aerial assault on Iran will close within two months.

In normal winter weather conditions, it would be very difficult to carry out such a complex assault.

Meanwhile, former Mossad chief Meir Dagan said yesterday that a military strike on Iran is "far from being Israel's preferred option." Addressing the Council for Peace and Security, he explained, "there are currently tools and methods that are much more effective."

Dagan also said Iran's nuclear program is still far from the point of no return, and that Iran's situation is "the most problematic it has been in since the revolution" in 1979.

But Israel's strategic situation is also "the worst in its history," he warned, and Israel itself has contributed a lot to this deterioration. As an example, he cited Deputy Foreign Minister Danny Ayalon's decision to humiliate the Turkish ambassador last year by demonstratively seating him on a low chair.

Panetta, for his part, urged Israel to conduct negotiations on a two-state solution with the Palestinian Authority. Earlier, in a conversation with American journalists on the flight over, he had warned that Israel was suffering regional isolation following the crises in its relations with Turkey and Egypt.

Asked by reporters why the United States refuses to free Jonathan Pollard, who is serving a life sentence for spying on Israel's behalf, Panetta replied merely that there is much opposition to freeing Pollard from within the administration, given the serious crimes of which he was convicted. Consequently, he said, U.S. President Barack Obama "and others" have made it clear that it won't happen.

Panetta also met with Prime Minister Benjamin Netanyahu, as well as with senior PA officials in Ramallah. His next stop is Egypt, where, according to reports in the Arab media, he will also discuss the release of Israeli-American Ilan Grapel, who was arrested a few months ago on suspicion of espionage.