Former Mossad head Meir Dagan believes that an air force strike against Iran's nuclear installations would be "a stupid thing." His statement is an unprecedented challenge to Prime Minister Benjamin Netanyahu who is trying to give the impression that he believes the air force should attack Iran.

In the past Dagan had expressed his opposition to an Israeli military strike against Iran but his statements were not as blatant and were voiced in closed sessions, quoted in the media as originating from "a senior security source."

This time he spoke in public at a conference of the senior public service organization, held at Hebrew University. This was Dagan's first public appearance since he left the service at the end of 2010.

Dagan says that Iran has a secret infrastructure for its nuclear program which is working in parallel with the legitimate, civilian program, but only the latter is under international inspection.

"Any strike against that [the civilian program] is an illegal act according to international law," Dagan said. Dagan says that contrary to the situation in Iraq in which the nuclear plant of Saddam Hussein was bombed in 1981, Iran has dispersed its nuclear sites across the country, making an effective attack difficult. He added that Iran has a proven ability to move its nuclear infrastructures from place to place, in order to hide them from international inspectors and intelligence services.

"If someone in Iran decides to build a laboratory for centrifuges [for uranium enrichment] in the basement of some school he has no problem doing this," Dagan said.

The former Mossad chief stressed that the problem "is not that our air force is not good. It is. But there is great doubt about its ability to carry out the mission fully and achieve all the goals. The biggest question is what will happen afterwards. There will be war with Iran, which is one of those things which we know how it starts but not how it finishes. An analysis of Iran's capabilities - they have impressive capabilities and they can shoot missiles at us for many months. Assuming the rate is two or three per day, and then use Hezbollah, which has tens of thousands of Grad-type rockets and hundreds of long-range missiles, Scuds and others. In addition they will use Hamas. There is also a risk that Syria will enter the war."

Dagan warned that an air force strike against Iran has "potential for significant complications and it is best to avoid war (s ) with non-beneficial results and also those with no lasting effect. It is important to remember that war is only one option among many alternatives."

Responding to a question on what Israel should do, he said "what is being done to Iran, and is reported in the media [the international media], is working." He was referring to the reports about clandestine sabotage against the Iranian efforts to achieve nuclear capability.

Dagan also said that "there are endless power struggles in Iran between the various groups and the assumption that the regime is homogeneous is entirely unrealistic."

He said that the lack of harmony in Iran applies to its nuclear policy and to its policy on the Middle East. Dagan noted that Iran's top priority is developments in Iraq, and its second priority is the struggle against the United States for influence in the Persian Gulf.

As for developments in the Arab world Dagan said that he does not read the situation as a "tsunami of change in the Middle East." What is happening reflects historical divisions in Arab societies.

Regarding Egypt, Dagan said that what accelerated the process which led the masses to the streets was not "the Internet revolution," given the lack of computers for the masses. He said that the catalyst stemmed from the ambition of Hosni Mubarak's wife to see their son, Gamal, succeed his father as president. This angered the Egyptians and brought the masses to the street.

Dagan said that what happened in Egypt was not a revolution, but a change in leadership. He also believes there is no risk of the Muslim Brotherhood taking over because they themselves fear that this would irreparably harm the Egyptian economy.

He said that it would be better for Israel if Bashar Assad was removed from power because this would stem support for Hezbollah and undermine Iran's involvement in the area, giving greater say to moderate Sunni forces.