JERUSALEM (AP) — The recently retired head of the Mossad intelligence agency has said Israel must consider alternatives to a military strike on Iran’s nuclear facilities, but another expert said Friday an Israeli attack could come within months.

Ex-Mossad director Meir Dagan pointed to a need for caution after Israel’s prime minister hinted Israel might feel the need to attack. Among the alternative actions he suggested was supporting Iranian opposition groups working for regime change.

“An attack on Iran before you are exploring all other approaches is not the right way how to do it,” Meir Dagan said to CBS’s 60 Minutes, according to a transcript of a program that airs on Sunday.

After returning from talks in Washington, Prime Minister Benjamin Netanyahu told local TV stations late Thursday that he prefers a diplomatic solution, but left the military option on the table.

“We won’t accept a situation where Iran has nuclear weapons, because we face an existential threat,” Netanyahu said.

Netanyahu told local media that a strike on Iran “is not a matter of days or weeks, but it’s also not a matter of years.”

Netanyahu’s former security adviser, Uzi Arad, told Army Radio Friday he believed Netanyahu’s timetable narrowed down the options for a military strike: “What’s left? A matter of months.”

Uzi Arad, Benjamin Netanyahu's former national security adviser. (photo credit: Kobi Gideon/Flash90)

Uzi Arad, Benjamin Netanyahu's former national security adviser. (photo credit: Kobi Gideon/Flash90)

Dagan told CBS he believed there was “more time” to try other options of engagement with Iran, instead of military action.

“It’s our duty to help anyone who likes to present an open opposition against their regime in Iran,” he said, according to text excerpts of the interview which CBS released ahead of its full broadcast Sunday.

Dagan took over the Mossad in 2002 and retired in early 2011. During his tenure, the Mossad is thought to have played a role in clandestine efforts to slow down Iran’s nuclear research, including assassinations of Iranian nuclear scientists and computer viruses that disrupted research facilities.

Since retiring from the intelligence agency, he has spoken out publicly against a possible Israeli military strike on Iran.

He would not say if Israel has supported opposition groups who publicly protested against the regime in the past.

While Netanyahu told a pro-Israel committee in Washington that Iran’s leadership was one of “the world’s most dangerous regimes” which will be “even more reckless and a lot more dangerous” with nuclear weapons,” Dagan offered a more measured assessment.

“The Iranian regime is maybe not exactly rational, based on what I call Western thinking, but no doubt they are considering all the implications of their actions,” Dagan told CBS. “I think the Iranians at this point in time are…very careful on the (nuclear) project.”

The former Israeli intelligence chief said if a military strike was necessary, said he would “prefer” the U.S. carry it out, not Israel.

U.S. Defense Secretary Leon Panetta expressed a similar view in an interview to the National Journal published Thursday.

If Israel decided to attack Iran, “there’s no question that it would have an impact, but I think it’s also clear that if the United States did it we would have a hell of a bigger impact,” Panetta said.

Recent polls have suggested that a majority of Israelis oppose an Israeli strike on Iran if carried out without U.S. cooperation.

Copyright 2012 The Associated Press.